Systems and methods for robot-assisted knee arthroplasty surgery

ABSTRACT

A blade adapter couples a sagittal saw handpiece to an end effector of a robot to actuate a saw blade. The end effector has a first mechanical interface, and the sagittal saw handpiece has a second mechanical interface. The blade adapter includes a first coupling mechanism at a first side of the blade adapter and a second coupling mechanism at a second side of the blade adapter. The first coupling mechanism is coupleable to the first mechanical interface, and the second coupling mechanism is coupleable to the second mechanical interface.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional PatentApplication No. 63/088,593, filed Oct. 7, 2020. This application is alsoa continuation-in-part of U.S. application Ser. No. 16/737,054, filed onJan. 8, 2020, which (ii) is a continuation-in-part of U.S. applicationSer. No. 16/587,203, filed on Sep. 30, 2019, and (ii) claims the benefitof U.S. Provisional Application No. 62/906,831, filed on Sep. 27, 2019,all of which are incorporated herein by reference in their entirety forall purposes.

FIELD

The present disclosure generally relates to robot-assisted kneearthroplasty surgery and, in particular, to a blade adapter for couplingan end effector to a sagittal saw handpiece.

BACKGROUND

There are a number of surgical interventions requiring osteotomy, i.e.cutting an anatomical structure such as a bone along a target plane.Total knee arthroplasty typically requires cutting both the femoralepiphysis and tibial epiphysis in order to remove the damaged bone andcartilage and install a knee prosthesis. A surgeon may perform five ormore cuts on the femur and one or more cuts on the tibia using anoscillating surgical saw although future implant designs could use lessnumber of cuts.

During orthopedic surgeries, including joints and knees, it is importantto accurately align and stabilize the saw while cutting a desiredlocation on a bone. The surgeon's limited visibility to the surgicalsite combined with the difficultly in controlling movement of the sawcreates a risk that an undesired part of a bone or adjacent tissuebecomes cut. Vibrations generated by the saw while cutting can reducethe accuracy of the cuts. During knee surgery, the precision of a bonecut (planar cuts) affects how precisely the implant can be connected tothe exposed bone.

Some orthopedic surgeries, which involve bone cutting with a saw, mayutilize a robotic system to hold and guide the saw. These roboticsystems are based on the attachment of a saw handpiece to a robotic armand assume that the saw blade vibrates in a certain predefined plane inreference to the handpiece. This approach includes disadvantages. Forexample, the saw blade oscillation mechanism and saw blade attachmentrigidity impacts directly the rigidity of saw blade guidance, while themechanical stack up tolerance between robotic arm, saw handpiece, andblade directly impact the positioning accuracy of blade within the 3Dspace. Moreover, the rigidity in some designs may induce a highfrequency torsional stress on the blade interface during use, whichoften leads to breakage of the saw blade at the blade interface due tofatigue. In addition, it may be difficult to integrate different powertools/saw handpieces with a robotic system due to the complexity of anexternal surface that needs to be held by the robot. Failure to securelyconstrain the saw blade may result in detachment of the saw blade duringuse.

BRIEF SUMMARY

In one aspect, a system is for robot-assisted knee arthroplasty surgery.The system includes an end effector having a first mechanical interface,a sagittal saw handpiece having a second mechanical interface, and ablade adapter configured to couple the end effector to the sagittal sawhandpiece. The blade adapter includes a first coupling mechanism at afirst side of the blade adapter and a second coupling mechanism at asecond side of the blade adapter. The first coupling mechanism iscoupleable to the first mechanical interface, and the second couplingmechanism coupleable to the second mechanical interface.

In another aspect, a blade adapter is provided for coupling an endeffector having a first mechanical interface to a sagittal saw handpiecehaving a second mechanical interface. The blade adapter includes a firstcoupling mechanism at a first side of the blade adapter and a secondcoupling mechanism at a second side of the blade adapter. The firstcoupling mechanism coupleable to the first mechanical interface, and thesecond coupling mechanism coupleable to the second mechanical interface.

In yet another aspect, a method is provided for coupling an end effectorhaving a first mechanical interface to a sagittal saw handpiece having asecond mechanical interface. The method includes providing a bladeadapter comprising a first coupling mechanism at a first side and asecond coupling mechanism at a second side, coupling the first couplingmechanism to the first mechanical interface, and coupling the secondcoupling mechanism to the second mechanical interface.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure will be better understood, and features, aspects andadvantages other than those set forth above will become apparent whenconsideration is given to the following detailed description thereof.Such detailed description makes reference to the following drawings,wherein:

FIG. 1 illustrates an embodiment of a surgical system according to someembodiments of the present disclosure;

FIG. 2 illustrates a surgical robot component of the surgical system ofFIG. 1 according to some embodiments of the present disclosure;

FIG. 3 illustrates a camera tracking system component of the surgicalsystem of FIG. 1 according to some embodiments of the presentdisclosure;

FIG. 4 illustrates an embodiment of a passive end effector that isconnectable to a robot arm and configured according to some embodimentsof the present disclosure;

FIG. 5 illustrates a medical operation in which a surgical robot and acamera system are disposed around a patient;

FIG. 6 illustrates an embodiment of an end effector coupler of a robotarm configured for connection to a passive end effector according tosome embodiments of the present disclosure;

FIG. 7 illustrates an embodiment of a cut away of the end effectorcoupler of FIG. 6;

FIG. 8 illustrates a block diagram of components of a surgical systemaccording to some embodiments of the present disclosure;

FIG. 9 illustrates a block diagram of a surgical system computerplatform that includes a surgical planning computer which may beseparate from and operationally connected to a surgical robot or atleast partially incorporated therein according to some embodiments ofthe present disclosure;

FIG. 10 illustrates an embodiment of a C-Arm imaging device that can beused in combination with the surgical robot and passive end effector inaccordance with some embodiments of the present disclosure;

FIG. 11 illustrates an embodiment of an O-Arm imaging device that can beused in combination with the surgical robot and passive end effector inaccordance with some embodiments of the present disclosure; and

FIGS. 12-19 illustrate alternative embodiments of passive end effectorswhich are configured in accordance with some embodiments of the presentdisclosure.

FIG. 20 is a screenshot of a display showing the progress of bone cutsduring a surgical procedure.

FIG. 21 illustrates an exemplary embodiment of a direct blade guidancesystem consistent with the principles of the present disclosure.

FIG. 22 illustrates an exemplary of a direct blade guidance systemconsistent with the principles of the present disclosure.

FIGS. 23-24 illustrate an exemplary embodiment of a portion of a directblade guidance system consistent with the principles of the presentdisclosure.

FIG. 25 illustrates an exemplary embodiment of a direct blade guidancesystem consistent with the principles of the present disclosure.

FIG. 26 illustrates an exemplary embodiment of a direct blade guidancesystem consistent with the principles of the present disclosure.

FIG. 27 illustrates an exemplary embodiment of a direct blade guidancesystem consistent with the principles of the present disclosure.

FIG. 28 illustrates an exemplary embodiment of a portion of a directblade guidance system consistent with the principles of the presentdisclosure.

FIGS. 29-30 illustrate an exemplary embodiment of a direct bladeguidance system consistent with the principles of the presentdisclosure.

FIG. 31 illustrates an exemplary embodiment of a blade adapterconsistent with the principles of the present disclosure.

FIG. 32 illustrates an exemplary embodiment of a direct blade guidancesystem consistent with the principles of the present disclosure.

FIG. 33 is a perspective view of an example system described herein.

FIGS. 34 and 35 are exploded views of the system shown in FIG. 1.

FIG. 36 is a detailed lower view of the system shown in FIG. 1.

FIG. 37 is a cross-sectional view of the system shown in FIG. 1.

FIG. 38 is a flowchart of an example method for coupling an end effectorto a sagittal saw handpiece.

FIG. 39 is a perspective view of another example system describedherein.

FIGS. 40 and 41 are exploded views of the system shown in FIG. 7.

FIG. 42 is a detailed lower view of the system shown in FIG. 7.

FIG. 43 is a cross-sectional view of the system shown in FIG. 7.

FIG. 44 is a perspective view of another example system describedherein.

FIGS. 45 and 46 are exploded views of the system shown in FIG. 12.

FIG. 47 is a detailed lower view of the system shown in FIG. 12.

FIG. 48 is a cross-sectional view of the system shown in FIG. 12.

FIGS. 49A and 49B show one aspect of the interface of the presentinvention.

FIG. 50 is a cross-sectional view of the interface of FIGS. 49A-49B asattached to an end effector.

In the drawings, reference numbers may be reused to identify similarand/or identical elements.

DETAILED DESCRIPTION

To overcome the above-noted issues and to implement the sought features,the present disclosure provides a blade adapter for coupling an endeffector to a sagittal saw handpiece. Inventive concepts will now bedescribed more fully hereinafter with reference to the accompanyingdrawings, in which various examples are shown. Inventive concepts may,however, be embodied in many different forms and should not be construedas limited to the examples set forth herein. Rather, these examples areprovided so that this disclosure will be thorough and complete, and willfully convey the scope of various present inventive concepts to thoseskilled in the art. It should also be noted that these examples are notmutually exclusive. Components from one example may be tacitly assumedto be present or used in another example.

Various examples disclosed herein are directed to improvements inoperation of a surgical system when performing surgical interventionsrequiring osteotomy. Surgical systems may include a surgical robot thatselectively positions an end effector and its functional part in the 3Dspace with respect to patient anatomy. Examples described herein includea first coupling mechanism coupleable to the end effector and a secondcoupling mechanism coupleable to a sagittal saw handpiece for use inmaking one or more cuts. The interface between the blade adapter and theend effector may include one or more sidewalls, stages, projections,cavities, slots, channels, openings, and the like to facilitate couplingthe blade adapter to the end effector. Additionally, the interfacebetween the blade adapter and the sagittal saw handpiece may include oneor more sidewalls, stages, projections, cavities, slots, channels,openings, and the like to facilitate coupling the blade adapter to thesagittal saw handpiece. In some examples, the first and second couplingmechanisms are on opposite sides of the blade adapter. For example, thefirst coupling mechanism may be at an upper side of the blade adapterfor use in coupling to a lower side of the end effector, and the secondcoupling mechanism may be at a lower side of the blade adapter for usein coupling to an upper side of the sagittal saw handpiece. In thismanner, the examples described herein are configured to securelyconstrain or retain the saw blade independent of the end effector and/orsagittal saw handpiece.

These and other related examples can operate to improve the precisionand reliability of the saw blade compared to other robotic and manualsolutions for surgeries. For example, by securely constraining orretaining the saw blade independent of the end effector and the sagittalsaw handpiece, the blade adapters described herein reduce the likelihoodof the saw blade breaking (e.g., due to misalignment of the bladeguidance and actuation axes) or of the sagittal saw handpieceself-detaching (e.g., due to blade oscillation) while the saw blade isguided (e.g., using the end effector) and/or actuated (e.g., using thesagittal saw handpiece). Moreover, by constraining the saw blade to acutting plane, the blade adapters described herein enable the saw bladeto make high-precision cuts. Furthermore, by providing a rigidconnection between the end effector and the sagittal saw handpiece, theblade adapters described herein allow a surgeon using the sagittal sawhandpiece to reliably interpret a force feedback of the saw blade whilemaking one or more cuts.

FIG. 1 illustrates an embodiment of a surgical system 2 according tosome embodiments of the present disclosure. Prior to performance of anorthopedic surgical procedure, a three-dimensional (“3D”) image scan maybe taken of a planned surgical area of a patient using, e.g., the C-Armimaging device 104 of FIG. 10 or O-Arm imaging device 106 of FIG. 11, orfrom another medical imaging device such as a computed tomography (CT)image or Mill. This scan can be taken pre-operatively (e.g. few weeksbefore procedure, most common) or intra-operatively. However, any known3D or 2D image scan may be used in accordance with various embodimentsof the surgical system 2. The image scan is sent to a computer platformin communication with the surgical system 2, such as the surgical systemcomputer platform 900 of FIG. 9 which includes the surgical robot 800(e.g., robot 2 in FIG. 1) and a surgical planning computer 910. Asurgeon reviewing the image scan(s) on a display device of the surgicalplanning computer 910 (FIG. 9) generates a surgical plan defining atarget plane where an anatomical structure of the patient is to be cut.This plane is a function of patient anatomy constraints, selectedimplant and its size. In some embodiments, the surgical plan definingthe target plane is planned on the 3D image scan displayed on a displaydevice.

The surgical system 2 of FIG. 1 can assist surgeons during medicalprocedures by, for example, holding tools, aligning tools, using tools,guiding tools, and/or positioning tools for use. In some embodiments,surgical system 2 includes a surgical robot 4 and a camera trackingsystem 6. Both systems may be mechanically coupled together by anyvarious mechanisms. Suitable mechanisms can include, but are not limitedto, mechanical latches, ties, clamps, or buttresses, or magnetic ormagnetized surfaces. The ability to mechanically couple surgical robot 4and camera tracking system 6 can allow for surgical system 2 to maneuverand move as a single unit, and allow surgical system 2 to have a smallfootprint in an area, allow easier movement through narrow passages andaround turns, and allow storage within a smaller area.

An orthopedic surgical procedure may begin with the surgical system 2moving from medical storage to a medical procedure room. The surgicalsystem 2 may be maneuvered through doorways, halls, and elevators toreach a medical procedure room. Within the room, the surgical system 2may be physically separated into two separate and distinct systems, thesurgical robot 4 and the camera tracking system 6. Surgical robot 4 maybe positioned adjacent the patient at any suitable location to properlyassist medical personnel. Camera tracking system 6 may be positioned atthe base of the patient, at patient shoulders or any other locationsuitable to track the present pose and movement of the pose of tracksportions of the surgical robot 4 and the patient. Surgical robot 4 andcamera tracking system 6 may be powered by an onboard power sourceand/or plugged into an external wall outlet.

Surgical robot 4 may be used to assist a surgeon by holding and/or usingtools during a medical procedure. To properly utilize and hold tools,surgical robot 4 may rely on a plurality of motors, computers, and/oractuators to function properly. Illustrated in FIG. 1, robot body 8 mayact as the structure in which the plurality of motors, computers, and/oractuators may be secured within surgical robot 4. Robot body 8 may alsoprovide support for robot telescoping support arm 16. In someembodiments, robot body 8 may be made of any suitable material. Suitablematerial may be, but is not limited to, metal such as titanium,aluminum, or stainless steel, carbon fiber, fiberglass, or heavy-dutyplastic. The size of robot body 8 may provide a solid platformsupporting attached components, and may house, conceal, and protect theplurality of motors, computers, and/or actuators that may operateattached components.

Robot base 10 may act as a lower support for surgical robot 4. In someembodiments, robot base 10 may support robot body 8 and may attach robotbody 8 to a plurality of powered wheels 12. This attachment to wheelsmay allow robot body 8 to move in space efficiently. Robot base 10 mayrun the length and width of robot body 8. Robot base 10 may be about twoinches to about 10 inches tall. Robot base 10 may be made of anysuitable material. Suitable material may be, but is not limited to,metal such as titanium, aluminum, or stainless steel, carbon fiber,fiberglass, or heavy-duty plastic or resin. Robot base 10 may cover,protect, and support powered wheels 12.

In some embodiments, as illustrated in FIG. 1, at least one poweredwheel 12 may be attached to robot base 10. Powered wheels 12 may attachto robot base 10 at any location. Each individual powered wheel 12 mayrotate about a vertical axis in any direction. A motor may be disposedabove, within, or adjacent to powered wheel 12. This motor may allow forsurgical system 2 to maneuver into any location and stabilize and/orlevel surgical system 2. A rod, located within or adjacent to poweredwheel 12, may be pressed into a surface by the motor. The rod, notpictured, may be made of any suitable metal to lift surgical system 2.Suitable metal may be, but is not limited to, stainless steel, aluminum,or titanium. Additionally, the rod may comprise at thecontact-surface-side end a buffer, not pictured, which may prevent therod from slipping and/or create a suitable contact surface. The materialmay be any suitable material to act as a buffer. Suitable material maybe, but is not limited to, a plastic, neoprene, rubber, or texturedmetal. The rod may lift powered wheel 10, which may lift surgical system2, to any height required to level or otherwise fix the orientation ofthe surgical system 2 in relation to a patient. The weight of surgicalsystem 2, supported through small contact areas by the rod on eachwheel, prevents surgical system 2 from moving during a medicalprocedure. This rigid positioning may prevent objects and/or people frommoving surgical system 2 by accident.

Moving surgical system 2 may be facilitated using robot railing 14.Robot railing 14 provides a person with the ability to move surgicalsystem 2 without grasping robot body 8. As illustrated in FIG. 1, robotrailing 14 may run the length of robot body 8, shorter than robot body8, and/or may run longer the length of robot body 8. Robot railing 14may be made of any suitable material. Suitable material may be, but isnot limited to, metal such as titanium, aluminum, or stainless steel,carbon fiber, fiberglass, or heavy-duty plastic. Robot railing 14 mayfurther provide protection to robot body 8, preventing objects and orpersonnel from touching, hitting, or bumping into robot body 8.

Robot body 8 may provide support for a Selective Compliance ArticulatedRobot Arm, hereafter referred to as a “SCARA.” A SCARA 24 may bebeneficial to use within the surgical system 2 due to the repeatabilityand compactness of the robotic arm. The compactness of a SCARA mayprovide additional space within a medical procedure, which may allowmedical professionals to perform medical procedures free of excessclutter and confining areas. SCARA 24 may comprise robot telescopingsupport 16, robot support arm 18, and/or robot arm 20. Robot telescopingsupport 16 may be disposed along robot body 8. As illustrated in FIG. 1,robot telescoping support 16 may provide support for the SCARA 24 anddisplay 34. In some embodiments, robot telescoping support 16 may extendand contract in a vertical direction. Robot telescoping support 16 maybe made of any suitable material. Suitable material may be, but is notlimited to, metal such as titanium or stainless steel, carbon fiber,fiberglass, or heavy-duty plastic. The body of robot telescoping support16 may be any width and/or height in which to support the stress andweight placed upon it.

In some embodiments, medical personnel may move SCARA 24 through acommand submitted by the medical personnel. The command may originatefrom input received on display 34 and/or a tablet. The command may comefrom the depression of a switch and/or the depression of a plurality ofswitches. Best illustrated in FIGS. 4 and 5, an activation assembly 60may include a switch and/or a plurality of switches. The activationassembly 60 may be operable to transmit a move command to the SCARA 24allowing an operator to manually manipulate the SCARA 24. When theswitch, or plurality of switches, is depressed the medical personnel mayhave the ability to move SCARA 24 easily. Additionally, when the SCARA24 is not receiving a command to move, the SCARA 24 may lock in place toprevent accidental movement by personnel and/or other objects. Bylocking in place, the SCARA 24 provides a solid platform upon which apassive end effector 1100 and connected surgical saw 1140, shown inFIGS. 4 and 5, are ready for use in a medical operation.

Robot support arm 18 may be disposed on robot telescoping support 16 byvarious mechanisms. In some embodiments, best seen in FIGS. 1 and 2,robot support arm 18 rotates in any direction in regard to robottelescoping support 16. Robot support arm 18 may rotate three hundredand sixty degrees around robot telescoping support 16. Robot arm 20 mayconnect to robot support arm 18 at any suitable location. Robot arm 20may attach to robot support arm 16 by various mechanisms. Suitablemechanisms may be, but is not limited to, nuts and bolts, ball andsocket fitting, press fitting, weld, adhesion, screws, rivets, clamps,latches, and/or any combination thereof. Robot arm 20 may rotate in anydirection in regards to robot support arm 18, in embodiments, robot arm20 may rotate three hundred and sixty degrees in regards to robotsupport arm 18. This free rotation may allow an operator to positionrobot arm 20 as planned.

The passive end effector 1100 in FIGS. 4 and 5 may attach to robot arm20 in any suitable location. As will be explained in further detailbelow, the passive end effector 1100 includes a base, a first mechanism,and a second mechanism. The base is configured to attach to an endeffector coupler 22 of the robot arm 20 positioned by the surgical robot4. Various mechanisms by which the base can attach to the end effectorcoupler 22 can include, but are not limited to, latch, clamp, nuts andbolts, ball and socket fitting, press fitting, weld, adhesion, screws,rivets, and/or any combination thereof. The first mechanism extendsbetween a rotatable connection to the base and a rotatable connection toa tool attachment mechanism. The second mechanism extends between arotatable connection to the base and a rotatable connection to the toolattachment mechanism. The first and second mechanisms pivot about therotatable connections, and may be configured to constrain movement ofthe tool attachment mechanism to a range of movement within a workingplane. The rotatable connections may be pivot joints allowing 1degree-of-freedom (DOF) motion, universal joints allowing 2 DOF motions,or ball joints allowing 3 DOF motions. The tool attachment mechanism isconfigured to connect to a surgical saw 1140 having a saw blade or sawblade directly. The surgical saw 1140 may be configured to oscillate thesaw blade for cutting. The first and second mechanisms may be configuredto constrain a cutting plane of the saw blade to be parallel to theworking plane. Pivot joints may be preferably used for connecting theplanar mechanisms when the passive end effector is to be configured toconstrain motion of the saw blade to the cutting plane.

The tool attachment mechanism may connect to the surgical saw 1140 orsaw blade through various mechanisms that can include, but are notlimited to, a screw, nut and bolt, clamp, latch, tie, press fit, ormagnet. In some embodiments, a dynamic reference array 52 is attached tothe passive end effector 1100, e.g., to the tool attachment mechanism,and/or is attached to the surgical saw 1140. Dynamic reference arrays,also referred to as “DRAs” herein, are rigid bodies which may bedisposed on a patient, the surgical robot, the passive end effector,and/or the surgical saw in a navigated surgical procedure. The cameratracking system 6 or other 3D localization system is configured to trackin real-time the pose (e.g., positions and rotational orientations) oftracking markers of the DRA. The tracking markers may include theillustrated arrangement of balls or other optical markers. This trackingof 3D coordinates of tracking markers can allow the surgical system 2 todetermine the pose of the DRA 52 in any space in relation to the targetanatomical structure of the patient 50 in FIG. 5.

As illustrated in FIG. 1, a light indicator 28 may be positioned on topof the SCARA 24. Light indicator 28 may illuminate as any type of lightto indicate “conditions” in which surgical system 2 is currentlyoperating. For example, the illumination of green may indicate that allsystems are normal. Illuminating red may indicate that surgical system 2is not operating normally. A pulsating light may mean surgical system 2is performing a function. Combinations of light and pulsation may createa nearly limitless amount of combinations in which to communicate thecurrent operating conditions, states, or other operational indications.In some embodiments, the light may be produced by LED bulbs, which mayform a ring around light indicator 28. Light indicator 28 may comprise afully permeable material that may let light shine through the entiretyof light indicator 28.

Light indicator 28 may be attached to lower display support 30. Lowerdisplay support 30, as illustrated in FIG. 2 may allow an operator tomaneuver display 34 to any suitable location. Lower display support 30may attach to light indicator 28 by any suitable mechanism. Inembodiments, lower display support 30 may rotate about light indicator28. In embodiments, lower display support 30 may attach rigidly to lightindicator 28. Light indicator 28 may then rotate three hundred and sixtydegrees about robot support arm 18. Lower display support 30 may be ofany suitable length, a suitable length may be about eight inches toabout thirty four inches. Lower display support 30 may act as a base forupper display support 32.

Upper display support 32 may attach to lower display support 30 by anysuitable mechanism. Upper display support 32 may be of any suitablelength, a suitable length may be about eight inches to about thirty fourinches. In embodiments, as illustrated in FIG. 1, upper display support32 may allow display 34 to rotate three hundred and sixty degrees inrelation to upper display support 32. Likewise, upper display support 32may rotate three hundred and sixty degrees in relation to lower displaysupport 30.

Display 34 may be any device which may be supported by upper displaysupport 32. In embodiments, as illustrated in FIG. 2, display 34 mayproduce color and/or black and white images. The width of display 34 maybe about eight inches to about thirty inches wide. The height of display34 may be about six inches to about twenty two inches tall. The depth ofdisplay 34 may be about one-half inch to about four inches.

In embodiments, a tablet may be used in conjunction with display 34and/or without display 34. In embodiments, the table may be disposed onupper display support 32, in place of display 34, and may be removablefrom upper display support 32 during a medical operation. In additionthe tablet may communicate with display 34. The tablet may be able toconnect to surgical robot 4 by any suitable wireless and/or wiredconnection. In some embodiments, the tablet may be able to programand/or control surgical system 2 during a medical operation. Whencontrolling surgical system 2 with the tablet, all input and outputcommands may be duplicated on display 34. The use of a tablet may allowan operator to manipulate surgical robot 4 without having to move aroundpatient 50 and/or to surgical robot 4.

As illustrated in FIG. 5, camera tracking system 6 works in conjunctionwith surgical robot 4 through wired or wireless communication networks.Referring to FIGS. 1 and 5, camera tracking system 6 can include somesimilar components to the surgical robot 4. For example, camera body 36may provide the functionality found in robot body 8. Robot body 8 mayprovide the structure upon which camera 46 is mounted. The structurewithin robot body 8 may also provide support for the electronics,communication devices, and power supplies used to operate cameratracking system 6. Camera body 36 may be made of the same material asrobot body 8. Camera tracking system 6 may communicate directly to thetablet and/or display 34 by a wireless and/or wired network to enablethe tablet and/or display 34 to control the functions of camera trackingsystem 6.

Camera body 36 is supported by camera base 38. Camera base 38 mayfunction as robot base 10. In the embodiment of FIG. 1, camera base 38may be wider than robot base 10. The width of camera base 38 may allowfor camera tracking system 6 to connect with surgical robot 4. Asillustrated in FIG. 1, the width of camera base 38 may be large enoughto fit outside robot base 10. When camera tracking system 6 and surgicalrobot 4 are connected, the additional width of camera base 38 may allowsurgical system 2 additional maneuverability and support for surgicalsystem 2.

As with robot base 10, a plurality of powered wheels 12 may attach tocamera base 38. Powered wheel 12 may allow camera tracking system 6 tostabilize and level or set fixed orientation in regards to patient 50,similar to the operation of robot base 10 and powered wheels 12. Thisstabilization may prevent camera tracking system 6 from moving during amedical procedure and may keep camera 46 from losing track of one ormore DRAs 52 connected to an anatomical structure 54 and/or tool 58within a designated area 56 as shown in FIG. 5. This stability andmaintenance of tracking enhances the ability of surgical robot 4 tooperate effectively with camera tracking system 6. Additionally, thewide camera base 38 may provide additional support to camera trackingsystem 6. Specifically, a wide camera base 38 may prevent cameratracking system 6 from tipping over when camera 46 is disposed over apatient, as illustrated in FIG. 5. Without the wide camera base 38, theoutstretched camera 46 may unbalance camera tracking system 6, which mayresult in camera tracking system 6 falling over.

Camera telescoping support 40 may support camera 46. In embodiments,telescoping support 40 may move camera 46 higher or lower in thevertical direction. Telescoping support 40 may be made of any suitablematerial in which to support camera 46. Suitable material may be, but isnot limited to, metal such as titanium, aluminum, or stainless steel,carbon fiber, fiberglass, or heavy-duty plastic. Camera handle 48 may beattached to camera telescoping support 40 at any suitable location.Cameral handle 48 may be any suitable handle configuration. A suitableconfiguration may be, but is not limited to, a bar, circular,triangular, square, and/or any combination thereof. As illustrated inFIG. 1, camera handle 48 may be triangular, allowing an operator to movecamera tracking system 6 into a planned position before a medicaloperation. In embodiments, camera handle 48 may be used to lower andraise camera telescoping support 40. Camera handle 48 may perform theraising and lowering of camera telescoping support 40 through thedepression of a button, switch, lever, and/or any combination thereof.

Lower camera support arm 42 may attach to camera telescoping support 40at any suitable location, in embodiments, as illustrated in FIG. 1,lower camera support arm 42 may rotate three hundred and sixty degreesaround telescoping support 40. This free rotation may allow an operatorto position camera 46 in any suitable location. Lower camera support arm42 may be made of any suitable material in which to support camera 46.Suitable material may be, but is not limited to, metal such as titanium,aluminum, or stainless steel, carbon fiber, fiberglass, or heavy-dutyplastic. Cross-section of lower camera support arm 42 may be anysuitable shape. Suitable cross-sectional shape may be, but is notlimited to, circle, square, rectangle, hexagon, octagon, or i-beam. Thecross-sectional length and width may be about one to ten inches. Lengthof the lower camera support arm may be about four inches to aboutthirty-six inches. Lower camera support arm 42 may connect totelescoping support 40 by any suitable mechanism. Suitable mechanism maybe, but is not limited to, nuts and bolts, ball and socket fitting,press fitting, weld, adhesion, screws, rivets, clamps, latches, and/orany combination thereof. Lower camera support arm 42 may be used toprovide support for camera 46. Camera 46 may be attached to lower camerasupport arm 42 by any suitable mechanism. Suitable mechanism may be, butis not limited to, nuts and bolts, ball and socket fitting, pressfitting, weld, adhesion, screws, rivets, and/or any combination thereof.Camera 46 may pivot in any direction at the attachment area betweencamera 46 and lower camera support arm 42. In embodiments a curved rail44 may be disposed on lower camera support arm 42.

Curved rail 44 may be disposed at any suitable location on lower camerasupport arm 42. As illustrated in FIG. 3, curved rail 44 may attach tolower camera support arm 42 by any suitable mechanism. Suitablemechanism may be, but are not limited to nuts and bolts, ball and socketfitting, press fitting, weld, adhesion, screws, rivets, clamps, latches,and/or any combination thereof. Curved rail 44 may be of any suitableshape, a suitable shape may be a crescent, circular, oval, elliptical,and/or any combination thereof. In embodiments, curved rail 44 may beany appropriate length. An appropriate length may be about one foot toabout six feet. Camera 46 may be moveably disposed along curved rail 44.Camera 46 may attach to curved rail 44 by any suitable mechanism.Suitable mechanism may be, but are not limited to rollers, brackets,braces, motors, and/or any combination thereof. Motors and rollers, notillustrated, may be used to move camera 46 along curved rail 44. Asillustrated in FIG. 3, during a medical procedure, if an object preventscamera 46 from viewing one or more DRAs 52, the motors may move camera46 along curved rail 44 using rollers. This motorized movement may allowcamera 46 to move to a new position that is no longer obstructed by theobject without moving camera tracking system 6. While camera 46 isobstructed from viewing DRAs 52, camera tracking system 6 may send astop signal to surgical robot 4, display 34, and/or a tablet. The stopsignal may prevent SCARA 24 from moving until camera 46 has reacquiredDRAs 52. This stoppage may prevent SCARA 24 and/or end effector coupler22 from moving and/or using medical tools without being tracked bysurgical system 2.

End effector coupler 22, as illustrated in FIG. 6, is configured toconnect various types of passive end effectors to surgical robot 4. Endeffector coupler 22 can include a saddle joint 62, an activationassembly 60, a load cell 64 (FIG. 7), and a connector 66. Saddle joint62 may attach end effector coupler 22 to SCARA 24. Saddle joint 62 maybe made of any suitable material. Suitable material may be, but is notlimited to metal such as titanium, aluminum, or stainless steel, carbonfiber, fiberglass, or heavy-duty plastic. Saddle joint 62 may be made ofa single piece of metal which may provide end effector with additionalstrength and durability. The saddle joint 62 may attach to SCARA 24 byan attachment point 68. There may be a plurality of attachment points 68disposed about saddle joint 62. Attachment points 68 may be sunk, flush,and/or disposed upon saddle joint 62. In some examples, screws, nuts andbolts, and/or any combination thereof may pass through attachment point68 and secure saddle joint 62 to SCARA 24. The nuts and bolts mayconnect saddle joint 62 to a motor, not illustrated, within SCARA 24.The motor may move saddle joint 62 in any direction. The motor mayfurther prevent saddle joint 62 from moving from accidental bumps and/oraccidental touches by actively servoing at the current location orpassively by applying spring actuated brakes.

The end effector coupler 22 can include a load cell 64 interposedbetween the saddle join 62 and a connected passive end effector. Loadcell 64, as illustrated in FIG. 7 may attach to saddle joint 62 by anysuitable mechanism. Suitable mechanism may be, but is not limited to,screws, nuts and bolts, threading, press fitting, and/or any combinationthereof.

FIG. 8 illustrates a block diagram of components of a surgical system800 according to some embodiments of the present disclosure. Referringto FIGS. 7 and 8, load cell 64 may be any suitable instrument used todetect and measure forces. In some examples, load cell 64 may be a sixaxis load cell, a three-axis load cell or a uniaxial load cell. Loadcell 64 may be used to track the force applied to end effector coupler22. In some embodiments the load cell 64 may communicate with aplurality of motors 850, 851, 852, 853, and/or 854. As load cell 64senses force, information as to the amount of force applied may bedistributed from a switch array and/or a plurality of switch arrays to acontroller 846. Controller 846 may take the force information from loadcell 64 and process it with a switch algorithm. The switch algorithm isused by the controller 846 to control a motor driver 842. The motordriver 842 controls operation of one or more of the motors. Motor driver842 may direct a specific motor to produce, for example, an equal amountof force measured by load cell 64 through the motor. In someembodiments, the force produced may come from a plurality of motors,e.g., 850-854, as directed by controller 846. Additionally, motor driver842 may receive input from controller 846. Controller 846 may receiveinformation from load cell 64 as to the direction of force sensed byload cell 64. Controller 846 may process this information using a motioncontroller algorithm. The algorithm may be used to provide informationto specific motor drivers 842. To replicate the direction of force,controller 846 may activate and/or deactivate certain motor drivers 842.Controller 846 may control one or more motors, e.g. one or more of850-854, to induce motion of passive end effector 1100 in the directionof force sensed by load cell 64. This force-controlled motion may allowan operator to move SCARA 24 and passive end effector 1100 effortlesslyand/or with very little resistance. Movement of passive end effector1100 can be performed to position passive end effector 1100 in anysuitable pose (i.e., location and angular orientation relative todefined three-dimensional (3D) orthogonal reference axes) for use bymedical personnel.

Connector 66 is configured to be connectable to the base of the passiveend effector 1100 and is connected to load cell 64. Connector 66 caninclude attachment points 68, a sensory button 70, tool guides 72,and/or tool connections 74. Best illustrated in FIGS. 6 and 8, there maybe a plurality of attachment points 68. Attachment points 68 may connectconnector 66 to load cell 64. Attachment points 68 may be sunk, flush,and/or disposed upon connector 66. Attachment points 68 and 76 can beused to attach connector 66 to load cell 64 and/or to passive endeffector 1100. In some examples, Attachment points 68 and 76 may includescrews, nuts and bolts, press fittings, magnetic attachments, and/or anycombination thereof.

As illustrated in FIG. 6, a sensory button 70 may be disposed aboutcenter of connector 66. Sensory button 70 may be depressed when apassive end effector 1100 is connected to SCARA 24. Depression ofsensory button 70 may alert surgical robot 4, and in turn medicalpersonnel, that a passive end effector 1100 has been attached to SCARA24. As illustrated in FIG. 6, guides 72 may be used to facilitate properattachment of passive end effector 1100 to SCARA 24. Guides 72 may besunk, flush, and/or disposed upon connector 66. In some examples theremay be a plurality of guides 72 and may have any suitable patterns andmay be oriented in any suitable direction. Guides 72 may be any suitableshape to facilitate attachment of passive end effector 1100 to SCARA 24.A suitable shape may be, but is not limited to, circular, oval, square,polyhedral, and/or any combination thereof. Additionally, guides 72 maybe cut with a bevel, straight, and/or any combination thereof.

Connector 66 may have attachment points 74. As illustrated in FIG. 6,attachment points 74 may form a ledge and/or a plurality of ledges.Attachment points 74 may provide connector 66 a surface upon whichpassive end effector 1100 may clamp. In some embodiments, attachmentpoints 74 are disposed about any surface of connector 66 and oriented inany suitable manner in relation to connector 66.

Activation assembly 60, best illustrated in FIGS. 6 and 7, may encircleconnector 66. In some embodiments, activation assembly 60 may take theform of a bracelet that wraps around connector 66. In some embodiments,activation assembly 60, may be located in any suitable area withinsurgical system 2. In some examples, activation assembly 60 may belocated on any part of SCARA 24, any part of end effector coupler 22,may be worn by medical personnel (and communicate wirelessly), and/orany combination thereof. Activation assembly 60 may be made of anysuitable material. Suitable material may be, but is not limited toneoprene, plastic, rubber, gel, carbon fiber, fabric, and/or anycombination thereof. Activation assembly 60 may comprise of a primarybutton 78 and a secondary button 80. Primary button 78 and secondarybutton 80 may encircle the entirety of connector 66.

Primary button 78 may be a single ridge, as illustrated in FIG. 6, whichmay encircle connector 66. In some examples, primary button 78 may bedisposed upon activation assembly 60 along the end farthest away fromsaddle joint 62. Primary button 78 may be disposed upon primaryactivation switch 82, best illustrated on FIG. 7. Primary activationswitch 82 may be disposed between connector 66 and activation assembly60. In some examples, there may be a plurality of primary activationswitches 82, which may be disposed adjacent and beneath primary button78 along the entire length of primary button 78. Depressing primarybutton 78 upon primary activation switch 82 may allow an operator tomove SCARA 24 and end effector coupler 22. As discussed above, once setin place, SCARA 24 and end effector coupler 22 may not move until anoperator programs surgical robot 4 to move SCARA 24 and end effectorcoupler 22, or is moved using primary button 78 and primary activationswitch 82. In some examples, it may require the depression of at leasttwo non-adjacent primary activation switches 82 before SCARA 24 and endeffector coupler 22 will respond to operator commands. Depression of atleast two primary activation switches 82 may prevent the accidentalmovement of SCARA 24 and end effector coupler 22 during a medicalprocedure.

Activated by primary button 78 and primary activation switch 82, loadcell 64 may measure the force magnitude and/or direction exerted uponend effector coupler 22 by an operator, i.e. medical personnel. Thisinformation may be transferred to motors within SCARA 24 that may beused to move SCARA 24 and end effector coupler 22. Information as to themagnitude and direction of force measured by load cell 64 may cause themotors to move SCARA 24 and end effector coupler 22 in the samedirection as sensed by load cell 64. This force-controlled movement mayallow the operator to move SCARA 24 and end effector coupler 22 easilyand without large amounts of exertion due to the motors moving SCARA 24and end effector coupler 22 at the same time the operator is movingSCARA 24 and end effector coupler 22.

Secondary button 80, as illustrated in FIG. 6, may be disposed upon theend of activation assembly 60 closest to saddle joint 62. In someexamples secondary button 80 may comprise a plurality of ridges. Theplurality of ridges may be disposed adjacent to each other and mayencircle connector 66. Additionally, secondary button 80 may be disposedupon secondary activation switch 84. Secondary activation switch 84, asillustrated in FIG. 7, may be disposed between secondary button 80 andconnector 66. In some examples, secondary button 80 may be used by anoperator as a “selection” device. During a medical operation, surgicalrobot 4 may notify medical personnel to certain conditions by display 34and/or light indicator 28. Medical personnel may be prompted by surgicalrobot 4 to select a function, mode, and/or asses the condition ofsurgical system 2. Depressing secondary button 80 upon secondaryactivation switch 84 a single time may activate certain functions,modes, and/or acknowledge information communicated to medical personnelthrough display 34 and/or light indicator 28. Additionally, depressingsecondary button 80 upon secondary activation switch 84 multiple timesin rapid succession may activate additional functions, modes, and/orselect information communicated to medical personnel through display 34and/or light indicator 28. In some examples, at least two non-adjacentsecondary activation switches 84 may be depressed before secondarybutton 80 may function properly. This requirement may prevent unintendeduse of secondary button 80 from accidental bumping by medical personnelupon activation assembly 60. Primary button 78 and secondary button 80may use software architecture 86 to communicate commands of medicalpersonnel to surgical system 2.

FIG. 8 illustrates a block diagram of components of a surgical system800 configured according to some embodiments of the present disclosure,and which may correspond to the surgical system 2 above. Surgical system800 includes platform subsystem 802, computer subsystem 820, motioncontrol subsystem 840, and tracking subsystem 830. Platform subsystem802 includes battery 806, power distribution module 804, connector panel808, and charging station 810. Computer subsystem 820 includes computer822, display 824, and speaker 826. Motion control subsystem 840 includesdriver circuit 842, motors 850, 851, 852, 853, 854, stabilizers 855,856, 857, 858, end effector connector 844, and controller 846. Trackingsubsystem 830 includes position sensor 832 and camera converter 834.Surgical system 800 may also include a removable foot pedal 880 andremovable tablet computer 890.

Input power is supplied to surgical system 800 via a power source whichmay be provided to power distribution module 804. Power distributionmodule 804 receives input power and is configured to generate differentpower supply voltages that are provided to other modules, components,and subsystems of surgical system 800. Power distribution module 804 maybe configured to provide different voltage supplies to connector panel808, which may be provided to other components such as computer 822,display 824, speaker 826, driver 842 to, for example, power motors850-854 and end effector coupler 844, and provided to camera converter834 and other components for surgical system 800. Power distributionmodule 804 may also be connected to battery 806, which serves astemporary power source in the event that power distribution module 804does not receive power from an input power. At other times, powerdistribution module 804 may serve to charge battery 806.

Connector panel 808 may serve to connect different devices andcomponents to surgical system 800 and/or associated components andmodules. Connector panel 808 may contain one or more ports that receivelines or connections from different components. For example, connectorpanel 808 may have a ground terminal port that may ground surgicalsystem 800 to other equipment, a port to connect foot pedal 880, a portto connect to tracking subsystem 830, which may include position sensor832, camera converter 834, and marker tracking cameras 870. Connectorpanel 808 may also include other ports to allow USB, Ethernet, HDMIcommunications to other components, such as computer 822.

Control panel 816 may provide various buttons or indicators that controloperation of surgical system 800 and/or provide information fromsurgical system 800 for observation by an operator. For example, controlpanel 816 may include buttons to power on or off surgical system 800,lift or lower vertical column 16, and lift or lower stabilizers 855-858that may be designed to engage casters 12 to lock surgical system 800from physically moving. Other buttons may stop surgical system 800 inthe event of an emergency, which may remove all motor power and applymechanical brakes to stop all motion from occurring. Control panel 816may also have indicators notifying the operator of certain systemconditions such as a line power indicator or status of charge forbattery 806.

Computer 822 of computer subsystem 820 includes an operating system andsoftware to operate assigned functions of surgical system 800. Computer822 may receive and process information from other components (forexample, tracking subsystem 830, platform subsystem 802, and/or motioncontrol subsystem 840) in order to display information to the operator.Further, computer subsystem 820 may provide output through the speaker826 for the operator. The speaker may be part of the surgical robot,part of a head-mounted display component, or within another component ofthe surgical system 2. The display 824 may correspond to the display 34shown in FIGS. 1 and 2, or may be a head-mounted display which projectsimages onto a see-through display screen which forms an augmentedreality (AR) image that is overlaid on real-world objects viewablethrough the see-through display screen.

Tracking subsystem 830 may include position sensor 832 and cameraconverter 834. Tracking subsystem 830 may correspond to the cameratracking system 6 of FIG. 3. The marker tracking cameras 870 operatewith the position sensor 832 to determine the pose of DRAs 52. Thistracking may be conducted in a manner consistent with the presentdisclosure including the use of infrared or visible light technologythat tracks the location of active or passive elements of DRAs 52, suchas LEDs or reflective markers, respectively. The location, orientation,and position of structures having these types of markers, such as DRAs52, is provided to computer 822 and which may be shown to an operator ondisplay 824. For example, as shown in FIGS. 4 and 5, a surgical saw 1240having a DRA 52 or which is connected to an end effector coupler 22having a DRA 52 tracked in this manner (which may be referred to as anavigational space) may be shown to an operator in relation to a threedimensional image of a patient's anatomical structure.

Motion control subsystem 840 may be configured to physically movevertical column 16, upper arm 18, lower arm 20, or rotate end effectorcoupler 22. The physical movement may be conducted through the use ofone or more motors 850-854. For example, motor 850 may be configured tovertically lift or lower vertical column 16. Motor 851 may be configuredto laterally move upper arm 18 around a point of engagement withvertical column 16 as shown in FIG. 2. Motor 852 may be configured tolaterally move lower arm 20 around a point of engagement with upper arm18 as shown in FIG. 2. Motors 853 and 854 may be configured to move endeffector coupler 22 to provide translational movement and rotation alongin about three-dimensional axes. The surgical planning computer 910shown in FIG. 9 can provide control input to the controller 846 thatguides movement of the end effector coupler 22 to position a passive endeffector, which is connected thereto, with a planned pose (i.e.,location and angular orientation relative to defined 3D orthogonalreference axes) relative to an anatomical structure that is to be cutduring a surgical procedure. Motion control subsystem 840 may beconfigured to measure position of the passive end effector structureusing integrated position sensors (e.g. encoders). In one of theembodiments, position sensors are directly connected to at least onejoint of the passive end effector structure, but may also be positionedin another location in the structure and remotely measure the jointposition by interconnection of a timing belt, a wire, or any othersynchronous transmission interconnection.

FIG. 9 illustrates a block diagram of a surgical system computerplatform 900 that includes a surgical planning computer 910 which may beseparate from and operationally connected to a surgical robot 800 or atleast partially incorporated therein according to some embodiments ofthe present disclosure. Alternatively, at least a portion of operationsdisclosed herein for the surgical planning computer 910 may be performedby components of the surgical robot 800 such as by the computersubsystem 820.

Referring to FIG. 9, the surgical planning computer 910 includes adisplay 912, at least one processor circuit 914 (also referred to as aprocessor for brevity), at least one memory circuit 916 (also referredto as a memory for brevity) containing computer readable program code918, and at least one network interface 920 (also referred to as anetwork interface for brevity). The network interface 920 can beconfigured to connect to a C-Arm imaging device 104 in FIG. 10, an O-Armimaging device 106 in FIG. 11, another medical imaging device, an imagedatabase 950 of medical images, components of the surgical robot 800,and/or other electronic equipment.

When the surgical planning computer 910 is at least partially integratedwithin the surgical robot 800, the display 912 may correspond to thedisplay 34 of FIG. 2 and/or the tablet 890 of FIG. 8 and/or ahead-mounted display, the network interface 920 may correspond to theplatform network interface 812 of FIG. 8, and the processor 914 maycorrespond to the computer 822 of FIG. 8.

The processor 914 may include one or more data processing circuits, suchas a general purpose and/or special purpose processor, e.g.,microprocessor and/or digital signal processor. The processor 914 isconfigured to execute the computer readable program code 918 in thememory 916 to perform operations, which may include some or all of theoperations described herein as being performed by a surgical planningcomputer.

The processor 914 can operate to display on the display device 912 animage of a bone that is received from one of the imaging devices 104 and106 and/or from the image database 950 through the network interface920. The processor 914 receives an operator's definition of where ananatomical structure, i.e. one or more bones, shown in one or moreimages is to be cut, such as by an operator touch selecting locations onthe display 912 for planned surgical cuts or using a mouse-based cursorto define locations for planned surgical cuts.

The surgical planning computer 910 enables anatomy measurement, usefulfor knee surgery, like measurement of various angles determining centerof hip, center of angles, natural landmarks (e.g. transepicondylar line,Whitesides line, posterior condylar line etc.), etc. Some measurementscan be automatic while some others involve human input or assistance.This surgical planning computer 910 allows an operator to choose thecorrect implant for a patient, including choice of size and alignment.The surgical planning computer 910 enables automatic or semi-automatic(involving human input) segmentation (image processing) for CT images orother medical images. The surgical plan for a patient may be stored in acloud-based server for retrieval by the surgical robot 800. During thesurgery, the surgeon will choose which cut to make (e.g. posteriorfemur, proximal tibia etc.) using a computer screen (e.g. touchscreen)or augmented reality interaction via, e.g., a head-mounted display. Thesurgical robot 4 may automatically move the surgical saw blade to aplanned position so that a target plane of planned cut is optimallyplaced within a workspace of the passive end effector interconnectingthe surgical saw blade and the robot arm 20. Command enabling movementcan be given by user using various modalities, e.g. foot pedal.

In some embodiments, the surgical system computer platform 900 can usetwo DRAs to tracking patient anatomy position: one on patient tibia andone on patient femur. The platform 900 may use standard navigatedinstruments for the registration and checks (e.g., a pointer similar tothe one used in Globus ExcelsiusGPS system for spine surgery). Trackingmarkers allowing for detection of DRAs movement in reference to trackedanatomy can be used as well.

An important difficulty in knee surgery is how to plan the position ofthe implant in the knee and many surgeons struggle with to do it on acomputer screen which is a 2D representation of 3D anatomy. The platform900 could address this problem by using an augmented reality (AR)head-mounted display to generate an implant overlay around the actualpatient knee. For example, the surgeon can be operationally displayed avirtual handle to grab and move the implant to a desired pose and adjustplanned implant placement. Afterward, during surgery, the platform 900could render the navigation through the AR head-mounted display to showsurgeon what is not directly visible. Also, the progress of boneremoval, e.g., depth or cut, can be displayed in real-time. Otherfeatures that may be displayed through AR can include, withoutlimitation, gap or ligament balance along a range of joint motion,contact line on the implant along the range of joint motion, ligamenttension and/or laxity through color or other graphical overlays, etc.

The surgical planning computer 910, in some embodiments, can allowplanning for use of standard implants, e.g., posterior stabilizedimplants and cruciate retaining implants, cemented and cementlessimplants, revision systems for surgeries related to, for example, totalor partial knee and/or hip replacement and/or trauma.

The processor 912 may graphically illustrate on the display 912 one ormore cutting planes intersecting the displayed anatomical structure atthe locations selected by the operator for cutting the anatomicalstructure. The processor 912 also determines one or more sets of angularorientations and locations where the end effector coupler 22 must bepositioned so a cutting plane of the surgical saw blade will be alignedwith a target plane to perform the operator defined cuts, and stores thesets of angular orientations and locations as data in a surgical plandata structure. The processor 912 uses the known range of movement ofthe tool attachment mechanism of the passive end effector to determinewhere the end effector coupler 22 attached to the robot arm 20 needs tobe positioned.

The computer subsystem 820 of the surgical robot 800 receives data fromthe surgical plan data structure and receives information from thecamera tracking system 6 indicating a present pose of an anatomicalstructure that is to be cut and indicating a present pose of the passiveend effector and/or surgical saw tracked through DRAs. The computersubsystem 820 determines a pose of the target plane based on thesurgical plan defining where the anatomical structure is to be cut andbased on the pose of the anatomical structure. The computer subsystem820 generates steering information based on comparison of the pose ofthe target plane and the pose of the surgical saw. The steeringinformation indicates where the passive end effector needs to be movedso the cutting plane of the saw blade becomes aligned with the targetplane and the saw blade becomes positioned a distance from theanatomical structure to be cut that is within the range of movement ofthe tool attachment mechanism of the passive end effector.

As explained above, a surgical robot includes a robot base, a robot armconnected to the robot base, and at least one motor operativelyconnected to move the robot arm relative to the robot base. The surgicalrobot also includes at least one controller, e.g. the computer subsystem820 and the motion control subsystem 840, connected to the at least onemotor and configured to perform operations.

As will be explained in further detail below with regard to FIGS. 12-19,a passive end effector includes a base configured to attach to anactivation assembly of the robot arm, a first mechanism, and a secondmechanism. The first mechanism extends between a rotatable connection tothe base and a rotatable connection to a tool attachment mechanism. Thesecond mechanism extends between a rotatable connection to the base anda rotatable connection to the tool attachment mechanism. The first andsecond mechanisms pivot about the rotatable connections which may beconfigured to constrain movement of the tool attachment mechanism to arange of movement within a working plane. The rotatable connections maybe pivot joints allowing 1 degree-of-freedom (DOF) motion, universaljoints allowing 2 DOF motions, or ball joints allowing 3 DOF motions.The tool attachment mechanism is configured to connect to the surgicalsaw comprising a saw blade for cutting. The first and second mechanismsmay be configured to constrain a cutting plane of the saw blade to beparallel to the working plane.

In some embodiments, the operations performed by the at least onecontroller of the surgical robot also includes controlling movement ofthe at least one motor based on the steering information to repositionthe passive end effector so the cutting plane of the saw blade becomesaligned with the target plane and the saw blade becomes positioned thedistance from the anatomical structure to be cut that is within therange of movement of the tool attachment mechanism of the passive endeffector. The steering information may be displayed to guide anoperator's movement of the surgical saw and/or may be used by the atleast one controller to automatically move the surgical saw.

In one embodiment, the operations performed by the at least onecontroller of the surgical robot also includes providing the steeringinformation to a display device for display to guide operator movementof the passive end effector so the cutting plane of the saw bladebecomes aligned with the target plane and so the saw blade becomespositioned the distance from the anatomical structure, which is to becut, that is within the range of movement of the tool attachmentmechanism of the passive end effector. The display device may correspondto the display 824 (FIG. 8), the display 34 of FIG. 1, and/or ahead-mounted display.

For example, the steering information may be displayed on a head-mounteddisplay which projects images onto a see-through display screen whichforms an augmented reality image that is overlaid on real-world objectsviewable through the see-through display screen. The operations maydisplay a graphical representation of the target plane with a poseoverlaid on a bone and with a relative orientation there betweencorresponding to the surgical plan for how the bone is planned to becut. The operations may alternatively or additionally display agraphical representation of the cutting plane of the saw blade so thatan operator may more easily align the cutting plane with the plannedtarget plane for cutting the bone. The operator may thereby visuallyobserve and perform movements to align the cutting plane of the sawblade with the target plane so the saw blade becomes positioned at theplanned pose relative to the bone and within a range of movement of thetool attachment mechanism of the passive end effector.

An automated imaging system can be used in conjunction with the surgicalplanning computer 910 and/or the surgical system 2 to acquirepre-operative, intra-operative, post-operative, and/or real-time imagedata of a patient. Example automated imaging systems are illustrated inFIGS. 10 and 11. In some embodiments, the automated imaging system is aC-arm 104 (FIG. 10) imaging device or an O-arm® 106 (FIG. 11). (O-arm®is copyrighted by Medtronic Navigation, Inc. having a place of businessin Louisville, Colo., USA) It may be desirable to take x-rays of apatient from a number of different positions, without the need forfrequent manual repositioning of the patient which may be required in anx-ray system. C-arm 104 x-ray diagnostic equipment may solve theproblems of frequent manual repositioning and may be well known in themedical art of surgical and other interventional procedures. Asillustrated in FIG. 10, a C-arm includes an elongated C-shaped memberterminating in opposing distal ends 112 of the “C” shape. C-shapedmember is attached to an x-ray source 114 and an image receptor 116. Thespace within C-arm 104 of the arm provides room for the physician toattend to the patient substantially free of interference from the x-raysupport structure.

The C-arm is mounted to enable rotational movement of the arm in twodegrees of freedom, (i.e. about two perpendicular axes in a sphericalmotion). C-arm is slidably mounted to an x-ray support structure, whichallows orbiting rotational movement of the C-arm about its center ofcurvature, which may permit selective orientation of x-ray source 114and image receptor 116 vertically and/or horizontally. The C-arm mayalso be laterally rotatable, (i.e. in a perpendicular direction relativeto the orbiting direction to enable selectively adjustable positioningof x-ray source 114 and image receptor 116 relative to both the widthand length of the patient). Spherically rotational aspects of the C-armapparatus allow physicians to take x-rays of the patient at an optimalangle as determined with respect to the particular anatomical conditionbeing imaged.

The O-arm® 106 illustrated in FIG. 11 includes a gantry housing 124which may enclose an image capturing portion, not illustrated. The imagecapturing portion includes an x-ray source and/or emission portion andan x-ray receiving and/or image receiving portion, which may be disposedabout one hundred and eighty degrees from each other and mounted on arotor (not illustrated) relative to a track of the image capturingportion. The image capturing portion may be operable to rotate threehundred and sixty degrees during image acquisition. The image capturingportion may rotate around a central point and/or axis, allowing imagedata of the patient to be acquired from multiple directions or inmultiple planes.

The O-arm® 106 with the gantry housing 124 has a central opening forpositioning around an object to be imaged, a source of radiation that isrotatable around the interior of gantry housing 124, which may beadapted to project radiation from a plurality of different projectionangles. A detector system is adapted to detect the radiation at eachprojection angle to acquire object images from multiple projectionplanes in a quasi-simultaneous manner. The gantry may be attached to asupport structure O-arm® support structure, such as a wheeled mobilecart with wheels, in a cantilevered fashion. A positioning unittranslates and/or tilts the gantry to a planned position andorientation, preferably under control of a computerized motion controlsystem. The gantry may include a source and detector disposed oppositeone another on the gantry. The source and detector may be secured to amotorized rotor, which may rotate the source and detector around theinterior of the gantry in coordination with one another. The source maybe pulsed at multiple positions and orientations over a partial and/orfull three hundred and sixty degree rotation for multi-planar imaging ofa targeted object located inside the gantry. The gantry may furthercomprise a rail and bearing system for guiding the rotor as it rotates,which may carry the source and detector. Both and/or either O-arm® 106and C-arm 104 may be used as automated imaging system to scan a patientand send information to the surgical system 2.

Images captured by the automated imaging system can be displayed adisplay device of the surgical planning computer 910, the surgical robot800, and/or another component of the surgical system 2.

Various embodiments of passive end effectors that are configured for usewith a surgical system are now described in the context of FIGS. 12-19.

As will be explained in further detail below, the various passive endeffectors illustrated in FIGS. 12-19 each include a base, a first planermechanism, and a second planner mechanism. The base is configured toattach to an end effector coupler (e.g., end effector coupler 22 inFIGS. 4 and 5) of a robot arm (e.g., robot arm 18 in FIGS. 1 and 2)positioned by a surgical robot. Various clamping mechanisms may be usedto firmly attach the base to the end effector coupler, removing backlashand ensuring suitable stiffness. Irreversible clamping mechanisms whichmay be used to attach the base to the end effector coupler can includebut are not limited to toggle joint mechanisms or irreversible lockingscrew(s). A user may use an additional tool, such as but not limited to,a screwdriver, torque wrench, or driver to activate or tighten theclamping mechanism. The first mechanism extends between a rotatableconnection to the base of a two and a rotatable connection to a toolattachment mechanism. The second mechanism extends between a rotatableconnection to the base and a rotatable connection to the tool attachmentmechanism. The first and second mechanisms pivot about the rotatableconnections. The rotatable connections may be pivot joints allowing 1degree-of-freedom (DOF) motion, universal joints allowing 2 DOF motions,or ball joints allowing 3 DOF motions. When pivot joints are used thefirst and second mechanisms can be configured to constrain movement ofthe tool attachment mechanism to a range of movement within a workingplane. The tool attachment mechanism is configured to connect to asurgical saw having a saw blade that is configured to oscillate forcutting. The first and second mechanisms may be configured, e.g., viapivot joints having 1 DOF motion, to constrain a cutting plane of thesaw blade to be parallel to the working plane. The tool attachmentmechanism may connect to the surgical saw or saw blade through variousmechanisms that can include, but are not limited to, a screw, nut andbolt, clamp, latch, tie, press fit, or magnet. A DRA can be connected tothe tool attachment mechanism or the surgical saw to enable tracking ofa pose of the saw blade by the camera tracking system 6 (FIG. 3).

As explained above, a surgical system (e.g., surgical system 2 in FIGS.1 and 2) includes a surgical robot (e.g., surgical robot 4 in FIGS. 1and 2) and a tracking system (e.g., camera tracking system 6 in FIGS. 1and 3) that is configured to determine a pose of an anatomical structurethat is to be cut by the saw blade and to determine a pose of the sawblade. The surgical robot includes a robot base, a robot arm that isrotatably connected to the robot base and configured to position thepassive end effector. At least one motor is operatively connected tomove the robot arm relative to the robot base. At least one controlleris connected to the at least one motor and configured to performoperations that include determining a pose of a target plane based on asurgical plan defining where the anatomical structure is to be cut andbased on the pose of the anatomical structure, where the surgical planmay be generated by the surgical planning computer 910 of FIG. 9 basedon input from an operator, e.g., surgeon or other surgery personnel. Theoperations further include generating steering information based oncomparison of the pose of the target plane and the pose of the surgicalsaw. The steering information indicates where the passive end effectorneeds to be moved to position the working plane of the passive endeffector so the cutting plane of the saw blade is aligned with thetarget plane.

In some further embodiments, the operations performed by the at leastone controller further include controlling movement of the at least onemotor based on the steering information to reposition the passive endeffector so the cutting plane of the saw blade becomes aligned with thetarget plane and the saw blade becomes positioned a distance from theanatomical structure to be cut that is within the range of movement ofthe tool attachment mechanism of the passive end effector.

The operations may include providing the steering information to adisplay device for display to guide operator movement of the passive endeffector so the cutting plane of the saw blade becomes aligned with thetarget plane and so the saw blade becomes positioned a distance from theanatomical structure, which is to be cut, that is within the range ofmovement of the tool attachment mechanism of the passive end effector.

As explained above, some surgical systems can include head-mounteddisplay devices that can be worn by a surgeon, nurse practitioner,and/or other persons assisting with the surgical procedure. The surgicalsystems can display information that allows the wearer to position thepassive end effector more accurately and/or to confirm that it has beenpositioned accurately with the saw blade aligned with the target planefor cutting a planned location on an anatomical structure. The operationto provide the steering information to the display device, may includeconfiguring the steering information for display on a head-mounteddisplay device having a see-through display screen that displays thesteering information as an overlay on the anatomical structure that isto be cut to guide operator movement of the passive end effector so thecutting plane of the saw blade becomes aligned with the target plane andthe saw blade becomes positioned the distance from the anatomicalstructure within the range of movement of the tool attachment mechanismof the passive end effector.

The operation to configure the steering information for display on thehead-mounted display device, may include generating a graphicalrepresentation of the target plane that is displayed as an overlayanchored to and aligned with the anatomical structure that is to be cut,and generating another graphical representation of the cutting plane ofthe saw blade that is displayed as an overlay anchored to and alignedwith the saw blade. A wearer may thereby move the surgical saw toprovide visually observed alignment between the graphically renderedtarget plane and the graphically rendered cutting plane.

The operation to configure the steering information for display on thehead-mounted display device, may include generating a graphicalrepresentation a depth of cut made by the saw blade into a graphicalrepresentation of the anatomical structure being cut. Thus, the wearercan use the graphical representation of depth of cut to better monitorhow the saw blade is cutting through bone despite direct observation ofthe cutting being obstructed by tissue or other structure.

The tracking system can be configured to determine the pose of theanatomical structure that is to be cut by the saw blade based ondetermining a pose of tracking markers, e.g., DRAs, that are attached tothe anatomical structure, and can be configured to determine a pose ofthe surgical saw based on determining a pose of tracking markersconnected to at least one of the surgical saw and the passive endeffector. The tracking system can be configured to determine the pose ofthe surgical saw based on rotary position sensors which are configuredto measure rotational positions of the first and second mechanismsduring movement of the tool attachment mechanism within the workingplane. As explained above, position sensors may be directly connected toat least one joint of the passive end effector structure, but may alsobe positioned in another location in the structure and remotely measurethe joint position by interconnection of a timing belt, a wire, or anyother synchronous transmission interconnection. Additionally the pose ofthe saw blade can be determined based on the tracking markers attachedto the structure base, position sensors in the passive structure andkinematic model of the structure.

The various passive end effectors disclosed herein can be sterilizableor non-sterile (covered by a sterile drape) passive 3DOF (Degree OfFreedom) mechanical structures allowing mechanical guidance of asurgical saw or saw blade, such as a sagittal saw, along twotranslations in a plane parallel to the saw blade (defining the cutplane), and one rotation perpendicular to this cut plane (instrumentorientation). During the surgery, the surgical robot 4 moves the endeffector coupler 22, and the passive end effector and surgical sawattached there, automatically to a position close to a knee or otheranatomical structure, so that all bone to be cut is within the workspaceof the passive end effector. This position depends on the cut to be madeand the surgery planning and implant construction. The passive endeffector can have 3 DOF to guide sagittal saw or saw blade on thecutting plane providing two translation (X and Y directions) and arotation (around Z axis) as shown in FIG. 12.

When the surgical robot 4 achieves a planned position, it holds theposition (either on brakes or active motor control) and does not moveduring the particular bone cut. It is the passive end effector thatallows movement of the saw blade of the surgical saw along the plannedtarget plane. Such planar cuts are particularly useful for classicaltotal knee arthroplasty where all bone cuts are planar. In partial kneearthroplasty there are special types of implants, called “on-lay” whichcan be used in conjunction with saw-prepared bone surfaces. The variouspassive end effectors have mechanical structure that can ensureprecision of guidance during cuts, with higher precision than classicaljigs, and provide sufficient range of workspace range to cut all thebone that is planned and while provide sufficient transverse stiffness(corresponding to locked DOF) despite possibly significant amount ofvibrations originating from the surgical saw in addition to forcesapplied by the surgeon and bone reactionary forces.

As the same time, it is preferable to measure the passive end effectorposition because it enables the surgical robot 4 to inform the surgeonhow much bone has been removed (procedure advancement). One way toprovide real-time information on bone removal is for the surgical robot4 to measure where the saw blade passed in reference to the bone becausethe blade can pass only where the bone has been cut. To measure sawblade position a DRA can be mounted to the surgical saw and/or thepassive end effector. This enables direct or indirect measurement of thesaw position in 3D space. An alternative way to measure saw bladeposition is to integrate position (rotation or translation) sensors(e.g. encoders, resolvers) into position information of the passive endeffector in order to calculate position of the saw blade using amathematical model of a defined relationship between location of thepassive end effector geometry and the tip of the saw blade.

In one embodiment, a conventional sagittal saw mechanism can be usedwith the surgical system computer platform 900 with little or nochanges. The potential changes would involve adapting an external shieldto enable easy attachment of the surgical saw to the passive endeffector but would not necessarily involve changes in the internalmechanics. The passive end effector may be configured to connect to aconventional sagittal saw provided by, for example, DeSoutter company.In addition, the saw blade may be directly attached to the passive endeffector without the saw handpiece.

To prevent the saw from unintentional passive end effector movement whenthe surgical robot 4 positions the passive end effector, e.g., toprevent the surgical saw from falling on the patient due togravitational forces, the passive end effector can include a lockmechanism that moves between engaged and disengaged operations. Whileengaged, the lock mechanism prevents movement of the saw blade withrespect to the robot end effector coupler, either directly by lockingthe degree of freedoms (DOFs) of the surgical saw, or indirectly bybraking or locking specifics joints of the passive end effector. Whiledisengaged, the first and second mechanisms of the passive end effectorcan be moved relative to the base without interference from the lockmechanism. The lock mechanism may also be used when a surgeon holds thesurgical saw and controls the surgical robot 4 movement by applyingforces and torques to the surgical saw. The surgical robot 4, using theload cell 64 of FIGS. 6 and 7 integrated in the distal end of the robotarm 22, measures forces and torques that are applied and generatesresponsive forces and torques on the robot arm 22 so the surgeon canmore easily move the passive end effector back and forth, left andright, apply rotations around various axes.

A first embodiment of a passive end effector is shown in FIG. 12.Referring to FIG. 12, the passive end effector 1200 includes a base 1202configured to attach to an end effector coupler (e.g., end effectorcoupler 22 in FIGS. 4 and 5) of a robot arm (e.g., robot arm 18 in FIGS.1 and 2) positioned by a surgical robot. The passive end effector 1200further includes first and second mechanisms that extend betweenrotatable connections to the base 1202 and rotatable connections to atool attachment mechanism. The rotatable connections may be pivot jointsallowing 1 degree-of-freedom (DOF) motion, universal joints allowing 2DOF motions, or ball joints allowing 3 DOF motions. The first and secondmechanisms form a parallel architecture that positions the surgical sawrotation axis in the cut plane.

First and second link segments 1210 a and 1220 a form the first planermechanism, and third and fourth link segments 1210 b and 1220 b form thesecond planner mechanism. The first link segment 1210 a extends betweena rotatable connection to a first location on the base 1202 and arotatable connection to an end of the second link segment 1220 a. Thethird link segment 1210 b extends between a rotatable connection to asecond location on the base 1202 and a rotatable connection to an end ofthe fourth link segment 1220 b. The first and second locations on thebase 1202 are spaced apart on opposite sides of a rotational axis of thebase color to when rotated by the robot arm. The tool attachmentmechanism is formed by a fifth link segment that extends betweenrotatable connections to distal ends of the second link segment 1220 aand the fourth link segment 1220 b relative to the base 1202. The firstand second mechanisms (first and second link segments 1210 a-1220 a andthird and fourth link segments 1210 b-1220 b) pivot about theirrotatable connections to constrain movement of the tool attachmentmechanism 1230 to a range of movement within a working plane. The toolattachment mechanism 1230 is configured to connect to a surgical saw1240 having a saw blade 1242 that is configured to oscillate forcutting. The first and second mechanisms (first and second link segments1210 a-1220 a and third and fourth link segments 1210 b-1220 b) may beconfigured, e.g., via pivot joints having 1 DOF motion, to constrain acutting plane of the saw blade 1242 to be parallel to the working plane.The tool attachment mechanism 1230 may connect to the surgical saw 1240through various mechanisms that can include, but are not limited to, ascrew, nut and bolt, clamp, latch, tie, press fit, or magnet. A DRA 52can be connected to the tool attachment mechanism 1230 or the surgicalsaw 1240 to enable tracking of a pose of the saw blade 1242 by thecamera tracking system 6 (FIG. 3).

The passive end effector 1200 provides passive guidance of the surgicalsaw 1240 to constrain the saw blade 1242 to a defined cutting plane andreduce its mobility to three degrees of freedom (DOF): two translationsTx and Ty in a plane parallel to the cutting plane of the saw blade1242; and one rotational Rz around an axis perpendicular to the cuttingplane.

In some embodiments, a tracking system is configured to determine thepose of the saw blade 1242 based on rotary position sensors connected tothe rotational joints of at least some of the link segments of thepassive end effector 1200. The rotary position sensors are configured tomeasure rotational positions of the joined link segments during movementof the tool attachment mechanism within the working plane. For example,a rotary position sensor can be configured to measure rotation of thefirst link segment 1210 a relative to the base 1202, another rotaryposition sensor can be configured to measure rotation of the second linksegment 1220 a relative to the first link segment 1210 a, and anotherrotary position sensor can be configured to measure rotation of the toolattachment mechanism 1230 relative to the second link segment 1220 a.The surgical saw 1240 can connected to have a fixed orientation relativeto the tool attachment mechanism 1230. A serial kinematic chain of thepassive end effector 1200 connecting the saw blade 1242 and the robotarm 22, having serialized link segments and pivoting joints, providesthe required mobility to the surgical saw 1240. The position of the tipof the saw blade 1242 in the plane defined by the passive kinematicchain can be fully determined by the joint angles, sensed through therotary position sensors, and the structural geometry of theinterconnected link segments. Therefore, by measuring the relative anglebetween each connected link segment, for example along one or moreinterconnected paths between the base 1202 and the surgical saw 1240,the position of the tip of the saw blade 1242 in the cut space can becomputed using the proposed forward kinematic model. When the positionand orientation of robot arm 22 distal end position and orientation withrespect to the bone is known, the position and orientation of the sawblade 1242 with respect to the bone can be computed and displayed asfeedback to the surgeon. For exemplary implementations where the sawblade is directly attached to the passive end effector, the frequency ofmeasurement provided by rotary position sensors may be at least twotimes higher than saw blade oscillation frequency in order to measuresaw blade position even during oscillations.

Example types of rotary position sensors that can be used with passiveend effectors herein can include, but are not limited to:potentiometers; optical; capacitive; rotary variable differentialtransformer (RVDT); linear variable differential transformer (LVDT);Hall effect; and incoder.

A potentiometer based sensor is a passive electronic component.Potentiometers work by varying the position of a sliding contact acrossa uniform resistance. In a potentiometer, the entire input voltage isapplied across the whole length of the resistor, and the output voltageis the voltage drop between the fixed and sliding contact. To receiveand absolute position, a calibration-position is needed. Potentiometersmay have a measurement range smaller 360°.

An optical encoder can include a rotating disk, a light source, and aphoto detector (light sensor). The disk, which is mounted on therotating shaft, has patterns of opaque and transparent sectors codedinto the disk. As the disk rotates, these patterns interrupt the lightemitted onto the photo detector, generating a digital or pulse signaloutput. Through signal encoding on the disk absolute and relative aswell as multi-turn measurements are possible.

A capacitive encoder detects changes in capacitance using ahigh-frequency reference signal. This is accomplished with the threemain parts: a stationary transmitter, a rotor, and a stationaryreceiver. Capacitive encoders can also be provided in a two-partconfiguration, with a rotor and a combined transmitter/receiver. Therotor can be etched with a sinusoidal pattern, and as it rotates, thispattern modulates the high-frequency signal of the transmitter in apredictable way. The encoder can be multi-turn, but absolute measurementis difficult to realize. Calibration at startup is needed.

RVDT and LVDT sensors operate where the core of the transformer is innull position, the output voltages of the two, primary and secondary,windings are equal in magnitude, however opposite in direction. Theoverall output of the null position is always zero. An angulardisplacement from the null position is inducing a total differentialoutput voltage. Therefore, the total angular displacement is directlyproportional to the linear differential output voltage. The differentialoutput voltages increase with clockwise and decrease with anti-clockwisedirection. This encoder works in absolute measurement and may not bemulti-turn compatible. Calibration during assembly is needed.

In a Hall effect sensors, a thin strip of metal has a current appliedalong it. In the presence of a magnetic field, the electrons in themetal strip are deflected toward one edge, producing a voltage gradientacross the short side of the strip, i.e., perpendicular to the feedcurrent. In its simplest form, the sensor operates as an analogtransducer, directly returning a voltage. With a known magnetic field,its distance from the Hall plate can be determined. Using groups ofsensors, the relative position of the magnet can be deduced. Bycombining multiple sensor elements with a patterned magnet-plate,position can be detected absolute and relative similar to opticalencoders.

An incoder sensor works in a similar way to rotary variable transformersensor, brushless resolvers or synchros. The stator receives DC powerand produces a low power AC electromagnetic field between the stator androtor. This field is modified by the rotor depending on its angle. Thestator senses the resulting field and outputs the rotation angle as ananalogue or digital signal. Unlike resolvers, incoders use laminarcircuits rather than wound wire spools. This technology enables incoderscompact form, low mass, low inertia and high accuracy without highprecision installation. A signal (Z) to count one full rotation istransmitted. Multi-turn and absolute sensing is possible.

A second embodiment of a passive end effector is shown in FIG. 13.Referring to FIG. 13, the passive end effector 1300 includes a base 1302that is configured to attach to an end effector coupler (e.g., endeffector coupler 22 in FIGS. 4 and 5) of a robot arm (e.g., robot arm 18in FIGS. 1 and 2) positioned by a surgical robot. The passive endeffector 1300 further includes first and second mechanisms that extendbetween rotatable connections to the base 1302 and rotatable connectionsto a tool attachment mechanism. The rotatable connections may be pivotjoints allowing 1 DOF motion, universal joints allowing 2 DOF motions,or ball joints allowing 3 DOF motions. First and second link segments1310 a and 1320 a form the first planer mechanism, and third and fourthlink segments 1310 b and 1320 b form the second planner mechanism. Thefirst link segment 1310 a extends between a rotatable connection to afirst location on the base 1302 and a rotatable connection to an end ofthe second link segment 1320 a. The third link segment 1310 b extendsbetween a rotatable connection to a second location on the base 1302 anda rotatable connection to an end of the fourth link segment 1320 b. Thefirst and second locations on the base 1302 are spaced apart on oppositesides of a rotational axis of the base color to when rotated by therobot arm. Distal ends of the second link segment 1320 a and the fourthlink segment 1320 b from the base 1302 are rotatably connected to eachother and to the tool attachment mechanism 1330. The first and secondmechanisms (first and second link segments 1310 a-1320 a and third andfourth link segments 1310 b-1320 b) may be configured, e.g., via pivotjoints having 1 DOF motion, to rotate about their rotatable connectionsto constrain movement of the tool attachment mechanism 1330 to a rangeof movement within a working plane. The tool attachment mechanism 1330is configured to connect to a surgical saw 1240 having a saw blade 1242that is configured to oscillate for cutting. The first and secondmechanisms (first and second link segments 1310 a-1320 a and third andfourth link segments 1310 b-1320 b) constrain a cutting plane of the sawblade 1242 to be parallel to the working plane. The tool attachmentmechanism 1330 may connect to the surgical saw 1240 through variousmechanisms that can include, but are not limited to, a screw, nut andbolt, clamp, latch, tie, press fit, or magnet. A DRA can be connected tothe tool attachment mechanism 1330 or the surgical saw 1240 to enabletracking of a pose of the saw blade 1242 by the camera tracking system 6(FIG. 3).

A third embodiment of a passive end effector is shown in FIG. 14.Referring to FIG. 14, the passive end effector 1400 includes a base 1402that is configured to attach to an end effector coupler (e.g., endeffector coupler 22 in FIGS. 4 and 5) of a robot arm (e.g., robot arm 18in FIGS. 1 and 2) positioned by a surgical robot. The base 1402 includesfirst and second elongated base segments 1404 a and 1404 b that extendfrom spaced apart locations on opposite sides of a rotational axis ofthe base 1402 when rotated by the robot arm. The first and secondelongated base segments 1404 a and 1404 b extend in a direction awayfrom the end effector coupler of the robot arm when attached to thepassive end effector 1400. The passive end effector 1400 furtherincludes first and second mechanisms that extend between rotatableconnections to the elongated base segments 1404 a and 1404 b androtatable connections to a tool attachment mechanism. One or more of therotatable connections disclosed for this embodiment may be pivot jointsallowing 1 DOF motion, universal joints allowing 2 DOF motions, or balljoints allowing 3 DOF motions.

The first mechanism includes a first link segment 1411 a, the secondlink segment 1410 a, a third link segment 1420 a, and a fourth linksegment 1430 a. The first and second link segments 1411 a and 1410 aextend parallel to each other between rotatable connections to spacedapart locations on the first elongated base segment 1404 a and spacedapart locations on the third link segment 1420 a. An end of the thirdlink segment 1420 a is rotatably connected to an end of the fourth linksegment 1430 a.

The second mechanism includes a fifth link segment 1411 b, a sixth linksegment 1410 b, and a seventh link segment 1420 b. The fifth and sixthlink segments 1411 b and 1410 b extend parallel to each other betweenrotatable connections to spaced apart locations on the second elongatedbase segment 1404 b and spaced apart locations on the seventh linksegment 1420 b. The tool attachment mechanism includes an eighth linksegment 1440 that extends between rotatable connections to distal endsof the fourth and seventh link segments 1430 a and 1420 b from the base1402. In a further embodiment, the eighth link segment 1440 of the toolattachment mechanism includes an attachment member 1442 that extends ina direction away from the base 1402 to a rotatable connector that isconfigured to connect to the surgical saw 1240. The attachment member1442 extends from a location on the eighth link segment 1440 that iscloser to the fourth link segment 1430 a than to the seventh linksegment 1420 b.

The first and second mechanisms (set of link segments 1411 a, 1410 a,1420 a, 1430 a and set of link segments 1411 b, 1410 b, 1420 b) may beconfigured to pivot about their rotatable connections to constrainmovement of the tool attachment mechanism 1440 to a range of movementwithin a working plane. The tool attachment mechanism 1440 is configuredto connect to the surgical saw 1240 having the saw blade 1242 that isconfigured to oscillate for cutting. The first and second mechanisms maybe configured, e.g., via pivot joints having 1 DOF motion, to constraina cutting plane of the saw blade 1242 to be parallel to the workingplane. The tool attachment mechanism 1440 may connect to the surgicalsaw 1240 through various mechanisms that can include, but are notlimited to, a screw, nut and bolt, clamp, latch, tie, press fit, ormagnet. A DRA can be connected to the tool attachment mechanism 1440,such as to the attachment member 1442, or the surgical saw 1240 toenable tracking of a pose of the saw blade 1242 by the camera trackingsystem 6 (FIG. 3).

The passive end effector 1400 of FIG. 14 has a parallel architectureenabling positioning of the surgical saw about a rotation axis in thecut plane. Synchronized and/or different motion of lateralparallelograms allow positioning of the surgical saw rotation axis inthe cut plane.

A fourth embodiment of a passive end effector is shown in FIG. 15. Thepassive end effector 1500 includes a base 1502 that is configured toattach to an end effector coupler (e.g., end effector coupler 22 inFIGS. 4 and 5) of a robot arm (e.g., robot arm 18 in FIGS. 1 and 2)positioned by a surgical robot. The base 1502 may include first andsecond elongated base segments that extend from spaced apart locationson opposite sides of a rotational axis of the base 1502 when rotated bythe robot arm. The first and second elongated base segments extend awayfrom each other. The passive end effector 1500 further includes firstand second mechanisms that extend between rotatable connections to thebase 1502 and rotatable connections to a tool attachment mechanism. Oneor more of the rotatable connections disclosed for this embodiment maybe pivot joints allowing 1 DOF motion, universal joints allowing 2 DOFmotions, or ball joints allowing 3 DOF motions.

The first mechanism includes a first link segment 1510 a. The secondmechanism includes a second segment 1510 b. The tool attachmentmechanism includes a third link segment 1520, a fourth link segment1530, a fifth link segment 1540 a, a sixth link segment 1540 b, and aseventh link segment 1550. The first and second link segments 1510 a and1510 b extend between rotatable connections to first and secondlocations, respectively, on the base 1502, e.g., to first and secondelongated base segments extending away from the base 1502, to rotatableconnections at opposite ends of the third link segment 1520. The firstand second locations on the base 1502 are spaced apart on opposite sidesof a rotational axis of the base when rotated by the robot arm. Thefourth link segment 1530 extends from the third link segment 1520 in adirection towards the base 1502. The fifth and sixth link segments 1540a and 1540 b extend parallel to each other between rotatable connectionsto spaced apart locations on the fourth link segment 1530 and spacedapart locations on the seventh link segment 1550. The seventh linksegment 1550 is configured to have a rotatable connector that isconfigured to connect to the surgical saw 1240.

The first through sixth link segments 1510 a-b, 1520, 1530, and 1540 a-bmay be configured to pivot about their rotatable connections toconstrain movement of the seventh link segment 1550 to a range ofmovement within a working plane. The seventh link segment 1550 isconfigured to connect to the surgical saw 1240 having the saw blade 1242that is configured to oscillate for cutting. The first through sixthlink segments 1510 a-b, 1520, 1530, and 1540 a-b may be configured toconstrain a cutting plane of the saw blade 1242 to be parallel to theworking plane, e.g., via pivot joints having 1 DOF motion. The seventhlink segment 1550 may connect to the surgical saw 1240 through variousmechanisms that can include, but are not limited to, a screw, nut andbolt, clamp, latch, tie, press fit, or magnet. A DRA can be connected tothe seventh link segment 1550 or the surgical saw 1240 to enabletracking of a pose of the saw blade 1242 by the camera tracking system 6(FIG. 3).

A fifth embodiment of a passive end effector is shown in FIG. 16. Thepassive end effector 1600 includes a base 1602 that is configured toattach to an end effector coupler (e.g., end effector coupler 22 inFIGS. 4 and 5) of a robot arm (e.g., robot arm 18 in FIGS. 1 and 2)positioned by a surgical robot. The passive end effector 1600 furtherincludes first and second mechanisms that extend between rotatableconnections to the base 1502 and rotatable connections to a toolattachment mechanism. The first mechanism includes a first link segment1610 a. The second mechanism includes a second segment 1610 b. The toolattachment mechanism includes a third link segment 1620, a fourth linksegment 1630, a fifth link segment 1640 a, a sixth link segment 1640 b,and a seventh link segment 1650. One or more of the rotatableconnections disclosed for this embodiment may be pivot joints allowing 1DOF motion, universal joints allowing 2 DOF motions, or ball jointsallowing 3 DOF motions.

The first and second link segments 1610 a and 1610 b extend betweenrotatable connections to first and second locations, respectively, onthe base 1602 to rotatable connections at opposite ends of the thirdlink segment 1620. The first and second locations on the base 1602 arespaced apart on opposite sides of a rotational axis of the base 1602when rotated by the robot arm. The fourth link segment 1630 extends fromthe third link segment 1620 in a direction away from the base 1602. Thefifth and sixth link segments 1640 a and 1640 b extend parallel to eachother between rotatable connections to spaced apart locations on thefourth link segment 1630 and spaced apart locations on the seventh linksegment 1650. The seventh link segment 1650 is configured to have arotatable connector that is configured to connect to the surgical saw1240.

The first through sixth link segments 1610 a-b, 1620, 1630, and 1640 a-bmay be configured to pivot about their rotatable connections toconstrain movement of the seventh link segment 1650 to a range ofmovement within a working plane. The seventh link segment 1650 isconfigured to connect to the surgical saw 1240 having the saw blade 1242that is configured to oscillate for cutting. The first through sixthlink segments 1610 a-b, 1620, 1630, and 1640 a-b may be configured topivot while constraining a cutting plane of the saw blade 1242 to beparallel to the working plane. The seventh link segment 1650 may connectto the surgical saw 1240 through various mechanisms that can include,but are not limited to, a screw, nut and bolt, clamp, latch, tie, pressfit, or magnet. A DRA can be connected to the seventh link segment 1650or the surgical saw 1240 to enable tracking of a pose of the saw blade1242 by the camera tracking system 6 (FIG. 3).

The passive end effector 1600 provides two perpendicular translationalmovements for positioning the surgical saw rotation axis in the cuttingplane, and where the two translations are implemented by parallelograms.

A sixth embodiment of a passive end effector is shown in FIG. 17. Thepassive end effector 1700 includes a base 1702 that is configured toattach to an end effector coupler (e.g., end effector coupler 22 inFIGS. 4 and 5) of a robot arm (e.g., robot arm 18 in FIGS. 1 and 2)positioned by a surgical robot. The passive end effector 1700 furtherincludes first and second mechanisms that extend between rotatableconnections to the base 1702 and rotatable connections to a toolattachment mechanism. One or more of the rotatable connections disclosedfor this embodiment may be pivot joints allowing 1 DOF motion, universaljoints allowing 2 DOF motions, or ball joints allowing 3 DOF motions.The first and second mechanisms are connected to provide translationalong the radius of a parallelogram. The first mechanism includes firstand second link segments 1710 and 1720 b. The first link segment 1710extends between a rotatable connection to the base 1702 and a rotatableconnection to an end of the second link segment 1720 b. The secondmechanism includes a third link segment 1720 a. The tool attachmentmechanism includes a fourth link segment 1730. The second and third linksegments 1720 b and 1720 a extend away from the base 1702 and parallelto each other between rotatable connections to spaced apart locations onthe first link segment 1710 and spaced apart locations on the fourthlink segment 1730. The fourth link segment 1730 comprises an attachmentmember 1732 that extends in a direction away from the base to arotatable connector that is configured to connect to the surgical saw1240. The attachment member 1732 extends from a location on the fourthlink segment 1730 that is closer to the third link segment 1720 a thanto the second link segment 1720 b.

The first through third link segments 1710, 1720 b, 1720 a may beconfigured to pivot about their rotatable connections to constrainmovement of the fourth link segment 1730 to a range of movement within aworking plane. The fourth link segment 1730 is configured to connect tothe surgical saw 1240 having the saw blade 1242 that is configured tooscillate for cutting. The first through third link segments 1710, 1720b, 1720 a pivot and may be configured to constrain a cutting plane ofthe saw blade 1242 to be parallel to the working plane. The fourth linksegment 1730, e.g., the attachment member 1732 thereof, may connect tothe surgical saw 1240 through various mechanisms that can include, butare not limited to, a screw, nut and bolt, clamp, latch, tie, press fit,or magnet. A DRA can be connected to the fourth link segment 1730, e.g.,to the attachment member 1732, or the surgical saw 1240 to enabletracking of a pose of the saw blade 1242 by the camera tracking system 6(FIG. 3).

A seventh embodiment of a passive end effector is shown in FIG. 18. Thepassive end effector 1800 includes a base 1802 that is configured toattach to an end effector coupler (e.g., end effector coupler 22 inFIGS. 4 and 5) of a robot arm (e.g., robot arm 18 in FIGS. 1 and 2)positioned by a surgical robot. The passive end effector 1800 furtherincludes first and second mechanisms that extend between rotatableconnections to the base 1802 and rotatable connections to a toolattachment mechanism. One or more of the rotatable connections disclosedfor this embodiment may be pivot joints allowing 1 DOF motion, universaljoints allowing 2 DOF motions, or ball joints allowing 3 DOF motions.The first mechanism includes a first link segment 1810 a. The secondmechanism includes a second link segment 1810 b. The tool attachmentmechanism includes a third link segment 1820. The first and second linksegments 1810 a and 1810 b extend between rotatable connections to firstand second locations, respectively, on the base 1802 to rotatableconnections at opposite ends of the third link segment 1820. The firstand second locations on the base 1802 are spaced apart on opposite sidesof a rotational axis of the base 1802 when rotated by the robot arm. Thethird link segment 1820 includes an attachment member 1822 that extendsin a direction away from the base 1802 to a rotatable connector that isconfigured to connect to the surgical saw 1240. The attachment member1822 extends from a location on the third link segment 1820 that iscloser to the first link segment 1810 a than to the second link segment1810 b. One or more of the rotatable connections disclosed for thisembodiment may be pivot joints allowing 1 DOF motion, universal jointsallowing 2 DOF motions, or ball joints allowing 3 DOF motions.

The first and second link segments 1810 a and 1810 b may be configuredto pivot about their rotatable connections between the base 1802 and thethird link segment 1820 to constrain movement of the attachment member1822 to a range of movement within a working plane. In some otherembodiments one or more of the rotatable connections can be universaljoints allowing 2 DOF motions or ball joints allowing 3 DOF motions suchthat the movement is not constrained to the working plane. Theattachment member 1822 is configured to connect to the surgical saw 1240having the saw blade 1242 that is configured to oscillate for cutting.The first and second link segments 1810 a and 1810 b pivot whileconstraining a cutting plane of the saw blade 1242 to be parallel to theworking plane. The attachment member 1822 may connect to the surgicalsaw 1240 through various mechanisms that can include, but are notlimited to, a screw, nut and bolt, clamp, latch, tie, press fit, ormagnet. A DRA can be connected to the third link segment 1820, e.g., tothe attachment member 1822, or the surgical saw 1240 to enable trackingof a pose of the saw blade 1242 by the camera tracking system 6 (FIG.3).

An eighth embodiment of a passive end effector is shown in FIG. 19. Thepassive end effector 1900 includes a base 1902 that is configured toattach to an end effector coupler (e.g., end effector coupler 22 inFIGS. 4 and 5) of a robot arm (e.g., robot arm 18 in FIGS. 1 and 2)positioned by a surgical robot. The passive end effector 1900 furtherincludes a first link segment 1910 and a second link segment 1920. Thefirst link segment 1910 extends between a rotatable connection to thebase 1902 and a rotatable connection to one end of the second linksegment 1920. Another end of the second link segment 1920 is rotatablyconnected to a tool attachment mechanism. The rotational axes q1, q2 andq3 are parallel to each other so as to provide a planar cutting planefor the blade 1242. Thus, the 3 DOF motion of the saw 1240 includesx-direction Tx, y-direction Ty and rotational direction about z-axis Rz.One or more of the rotatable connections disclosed for this embodimentmay be pivot joints allowing 1 DOF motion, universal joints allowing 2DOF motions, or ball joints allowing 3 DOF motions.

The tracking markers 52 attached to the end effector base 1902 and thesaw 1240 along with the tracking markers on the bones (e.g., tibia andfemur) can be used to precisely and continuously monitor the real-timelocation of the blade 1242 and blade tip relative to the patient bonebeing cut. Although not explicitly shown in other figures, the trackingmarkers can be attached to the saw 1240 and all end effectors 1902 inall embodiments to track the location of the blade relative to thepatient bone being cut. Although not shown, alternatively or in additionto the tracking markers, encoders can be positioned in each of the linksegments 1910 and 1920 to determine precisely where the saw blade tip isat all times.

Example Surgical Procedure

An example surgical procedure using the surgical robot 4 in an OperatingRoom (OR) can include:

Optional step: surgery is pre-operatively planned based on medicalimages

-   -   1. The surgical robot 4 system is outside the Operating Room        (OR). The nurse brings the system to the OR when patient is        being prepared for the surgery.    -   2. The nurse powers on the robot and deploys the robot arm.        Nurse verifies precision of robotic and tracking systems.    -   3. In the case of a sterilized passive end effector, the scrub        nurse puts a sterile drape on the robot arm and mounts the        passive end effector with the sagittal saw on the robot arm. The        scrub nurse locks the passive end effector with a lock        mechanism. Scrub nurse attached DRAs to passive structure        through the drape (if necessary). For a non-sterilized passive        end effector, the drape is placed after attachment of the        passive end effector on the robot arm, the DRAs are attached to        the passive end effector with the drape intervening        therebetween, and a sterile saw or saw blade is attached to the        passive end effector with the drape intervening therebetween.        The lock mechanism is engaged, in order to fix position of the        saw blade with respect to the end effector coupler.    -   4. The surgeon attaches navigation markers to the patient's        bone(s), e.g., tibia and femur. The bones are registered with        the camera tracking system 6 using, e.g., Horn point-to-point        algorithm, surface matching or other algorithms. A soft-tissue        balance assessment may be performed, whereby the system allows        surgeon to assess balance of soft tissue in the operating room,        e.g., by tracking relative movement of femur and tibia when        surgeon applies forces in different directions (e.g.        varus/valgus stress). Soft-tissue balance information can be        used to alter surgical plan (e.g. move implant parts, change        implant type etc.).    -   5. When surgeon is ready to cut the bone, the scrub nurse brings        the surgical robot 4 to the operating table close to the knee to        be operated and stabilizes the surgical robot 4 on the floor.        The system may operate to guide nurse in finding robot 4        position so that all cut planes are in robot and passive        structure workspace.    -   6. The surgeon selects on the screen of the surgical robot 4 the        different parameters according to the planning of the surgery to        do the first cut (bone to be cut, cutting plan desired, etc.).    -   7. The surgical robot 4 automatically moves the robot arm 22 to        reposition the passive end effector so the cutting plane of the        saw blade becomes aligned with the target plane and the saw        blade becomes positioned a distance from the anatomical        structure to be cut that is within the range of movement of the        tool attachment mechanism of the passive end effector.    -   8. The surgeon unlocks the passive end effector.    -   9. The surgeon performs the cut constrained to the cutting plane        provide by the passive end effector. The surgical robot 4 may        provide real-time display of the tracked location of the saw        blade relative to bone so the surgeon can monitor progress of        bone removal. In one way, the tracking subsystem processes in        real-time the location of the saw relative to the bone based on        camera images and various tracking markers attached to the saw,        robot arm, end effector, femur and tibia. The surgeon can then        lock the passive end effector using the lock mechanism upon        completion of the cut.    -   10. The surgeon selects on the screen the next cut to be        executed and proceeds as before.    -   11. The surgeon may perform a trial implant placement and        intermediate soft-tissue balance assessment and based thereon        may change the implant plan and associated cuts.    -   12. Following completion of all cuts, the nurse removes the        surgical robot 4 from the operating table and unmounts the        passive end effector from the robot arm.    -   13. The surgeon places the implants and finishes the surgery.

In step 9 above, a physician may have a difficult time to visuallyconfirm the progress of the cut due to tissue and ligaments around thebone and debris being created from the cut, and other surgicalinstruments near the bone. Even if the visual confirmation may beacceptable, there are areas of the bone the physician cannot see such asthe posterior portion of the bone being cut.

Advantageously, one robotic system embodiment of the present inventionprovides a way for the physician to confirm the progress of the bonebeing cut in multiple dimensions. The camera tracking system 6 alongwith the tracking markers attached to the end effector base (1100, 1202,1302, 1402, 1502, 1602, 1702, 1802, 1902), robotic arm 20 and saw (1140,1240) allows the tracking subsystem 830 and the computer subsystem 820to calculate in real-time the precise position of the saw blade relativeto bone so the surgeon can monitor progress of bone removal.

FIG. 20 is a screenshot of a display showing the progress of bone cutsduring a surgical procedure. FIG. 20 shows the subsystems 830 and 820displaying three images: lateral, A-P and top views. In each image, thereal-time location of the saw blade 1242 relative to the bone (e.g.,tibia 2000) is displayed on the display 34. The lateral and top viewscan be especially useful for the physician as they display the saw bladeposition which cannot be easily seen. At the top portion of the display,the computer subsystem 830, 820 displays the number of cutting programsand what program it is currently running. For example as the screenshotshows, the physician may have programmed 6 planar cuts and the currentcutting program is the first one. Also, because the subsystems 830 and820 can track with tracking markers where the blade may have travelled,it can determine how much of the bone cutting (area that was cut) for aparticular cutting program has been completed and the percentage ofprogress is displayed in the display 34. The bone image itself ispreferably derived from actual images of the patient's body for a moreaccurate representation. The bone image is augmented by the subsystem820 with a contour line that shows the cortical bone 2004 and spongybone 2002. This can be important for a physician as the amount ofresistance to cutting varies greatly between the two types of bones.

If an augmented reality (AR) head-mounted display is used, the computersubsystem 820 can generate the same contour line showing the corticaland spongy bones and superimpose it over the actual leg continuously asthe physician moves his/her head. The area that has been already cut canbe overlaid over the actual bone in a dark shade. Moreover, the implantto be inserted over the cut area can also be overlaid on the bone toshow the physician that the cutting is being done correctly along theplane of the implant. This is all possible because the subsystems 830and 820 can track the position of the blade and history of its movementrelative to the bone with the tracking markers and the camera subsystem.

Referring now to FIGS. 21-32, an exemplary embodiment of a direct bladeguidance system in the context of orthopedic surgery is described. Asshown in FIGS. 21, 22, 29, and 30 a direct blade guidance system 2100may include a robotic system holding an end effector arm (EEA) 2102. EEA2102 may include a base configured to attach to an end effector couplerof a robot arm. Other exemplary embodiments of an end effector armconsistent with the principles of this disclosure are described withregard to FIGS. 12-19. In order to achieve planar cuts, a saw blade 2104should be guided in the plane in which it vibrates. Saw blade highvibration frequency (e.g. 200-300 Hz) makes it difficult to realizemechanical guidance. EEA 2102 may include several joints and linkages2106, 2108 that may be used to realize movement on the plane of a tip2110 of EEA 2102. Similar to embodiments of FIGS. 12-18, tip 2110 of EEA2102 may have three (3) degrees of freedom: movement in two directionson the plane and rotation around the axis normal to that plane. EEA 2102may allow planar cuts and approach the target bone from all angles.System 2100 may also include a handpiece 2112 and a blade adaptor 2114each connected to EEA 2102 and blade 2104.

The concept of directly guiding saw blade 2104 includes aligning therotation axis of a distal end of linkage 2110 (distal rotational joint2116 of EEA 2102) with a blade vibration axis. Sagittal saws are in themajority of implementation mechanisms which generate small rotationalmovement of the saw blade (vibration/oscillation) around an axis closeto the saw blade attachment. By aligning the rotation axis with thedistal rotational joint 2116 of EEA 2102 (at a distal end of linkage2108), joint 2116 may be configured to enable general saw handpiecerotation and enable saw blade vibration.

Saw blade 2104 may be configured to be linked to the distal jointrotation axis of EEA 2102 by blade adaptor 2114. Blade adaptor 2114 maybe configured to tighten saw blade 2104. By adapting the blade adaptor2114, different sagittal saws can be integrated into system 2100.Exemplary configurations for blade adaptor 2114 consistent with thepresent disclosure are discussed below. An exemplary blade adaptor isillustrated in FIG. 31.

Permanent Fixation

In a permanent fixation configuration, blade 2104 may be permanentlyclamped to blade adaptor 2114. A user (e.g., a scrub nurse) can assembleblade 2104 to blade adaptor 2114 while a surgeon is preparing a surgicalfield. Exemplary permanent fixation configurations may include thefollowing.

-   -   Blade 2104 may be firmly clamped to blade adaptor 2114 using a        component such as screws or spring loaded latches configured to        provide a clamping force against blade 2104.    -   Blade 2104 may include an interface, such as through holes, that        are configured to fix blade 2104 to blade adapter 2114.    -   Blade 2104 and blade adapter 2114 may be manufactured as a        single reusable device that is then provided on EEA 2102.        Example implementation involves a metal blade attached to a PEEK        or Stainless steel blade adapter. Assembly of the blade to the        blade adapter is performed by the scrub nurse.    -   Blade 2104 and blade adapter may also be manufactured as a        disposable (single use) device delivered sterile. Example        implementation involves a metal blade which is overmolded using        plastic injection molding technology.

FIG. 22 illustrates system 2200, which is an exemplary embodimentconsistent with the principles of the present disclosure. In thisembodiment, the blade adaptor is permanently affixed to the saw blade ina base that can rotate around the saw blade rotation axis and a clampingcomponent that clamps the blade to the blade adaptor base by means ofscrews. FIG. 23 illustrates a blade 2204, a blade adaptor 2214, a distalrotational joint 2216, and a clamp 2218 consistent with thisconfiguration. These components can be the same or similar to componentspreviously described with regard to FIG. 21.

Detachable Fixation

In a detachable fixation configuration, the blade can be quicklyattached to and detached from the blade adapter in the field. The bladeadaptor integrates a clamping mechanism that might be either active(normally closed clamping mechanism that is open by electrical signal)or passive (quick-coupling and/or quick-release mechanism).

Moment of Inertia

Blade adapter 2114 may significantly increase the moment of inertia ofthe coupled “blade/blade adapter” rotating around blade rotation axis.As soon as blade adapter 2114 vibrates together with saw blade 2104, theunbalanced inertia generates dynamic forces and torques that areexported to the mechanical structure as well as a surgeon's hand. Tooptimize the implementation, the inertia of the vibrating elementsaround the vibration axis may be minimized. That means the lighter andcloser the mass of the vibrating elements to the vibration axis, thebetter. The moment of inertia of the saw blade elements about thevibration axis for the handpiece guidance concept is:

I _(h) =I _(d) +MD ²

With D the distance between the blade vibration axis and the distaljoint rotation axis, M the weight of the blade (weight of the saw bladeelements) and I_(d) the moment of inertia of the saw blade elementsabout the blade vibration axis. The moment of inertia is then reduced byMD² with the direct blade guidance concept, which is the minimum as thedistance between the vibration axis and the blade vibration axis is 0(the axes are combined).

FIG. 24 illustrates a system using a standard jig 2402. Under theprinciples discussed herein, direct blade guidance may provide moreblade effective cutting length than those provided by standard jigs,such as jig 2402 illustrated in FIG. 24. L_(G) represents the guidinglength (length on which the saw blade is guided) and L_(E) representsthe blade effective length. As the guiding length can be made shorterwith the direct blade guidance concept, the blade effective length isconsequently longer. This is may be more comfortable for a surgeon andthe surgeon may cut through more bone.

The precision of the cut is given by the rigidity of the differentelements composing the robotic system from the floor to the tip of thesaw blade, including the robot system, EEA 2102, a handpiece sagittalsaw, a saw blade oscillation mechanism (such as blade adaptor 2114 or2214), and saw blade 2104, 2204. With the direct blade guidance, thebacklash and imprecisions of the handpiece may be significantlyminimized or prevented altogether because the saw blade is directlytightened with the blade adaptor.

Moreover, the direct blade guidance concept may be easier to integratewith various existing sagittal saws. There may be no need to build acomponent which is specific to the shape of the sagittal saw(manufacturer specific) because the blade adaptor is an element whichonly needs to tighten the saw blade whose shape may be simple. Inaddition, the blade adaptor is easy to sterilize. It is a small, lightand relatively simple mechanical element which can be made in such a waythat it does not have any narrow spaces and can be easily disassembled.As previously mentioned, blade including blade adaptor might bedelivered as single reusable device.

Tracking

FIG. 25 illustrates a direct blade guidance system 2100 that may includea navigation marker or array of markers 2500 attached to handpiece 2112of a sagittal saw. Marker 2500 allows the sagittal saw to be tracked bythe camera, such as camera tracking system 6. Optical tracking enablesmeasurement of the saw position but may it may be difficult to measure adirect saw blade position during cutting (high frequency of bladevibration). Moreover, the tracking would directly measure the deflectionof the saw handpiece 2112 with respect blade 2104, due to the poorstiffness of the blade/saw handpiece connection.

To measure a direct saw blade position, FIG. 26 illustrates system 2100with encoders 2600, 2602, and 2604 integrated to the joints of EEA 2102.Encoder measurement can be usually made at higher frequency androtational precision than using optical tracking. For example, themeasurement frequency can be at least two times higher than saw bladeoscillation. With a blade position signal, additional useful informationmay be extracted, such as saw vibration frequency, on/off state, sawblade blocking in bone (for example by interpreting the signal and itsderivatives) and others.

In exemplary embodiments consistent with the principles of thisdisclosure, vibrations of the sagittal saw handpiece held by the surgeonmay be reduced. By decreasing vibrations of the handpiece, tactilefeedback could be improved and cutting efficiency could be increased. Aspreviously described, the vibrations exported to surgeon's hand resultfrom the exported dynamic forces and torques generated by the unbalancedinertia of couple blade/blade adaptor around blade rotation axis.

One approach to reduce the vibrations may be achieved by filtering thevibrations. In FIG. 27, a damping element 2700 may be connected betweenhandpiece 2112 and the EEA 2102. This might be implemented using piecesof rubber, pneumatic or hydraulic cylinder. Another approach to reducethe vibrations may be achieved by dynamically balancing the inertia ofthe coupled saw/saw adaptor around the saw rotation axis. This can beimplemented by dynamically compensating the exported forces and torquesgenerated by the vibrating saw blade using a compensation inertia thatperforms the exact opposite movement with the same dynamics. FIGS. 28and 32 illustrates exemplary embodiments where compensation inertia canbe coupled to the main inertia to be balanced using a mechanicalinverter 2800.

Example Blade Adapters

Referring now to FIGS. 33-37, an example system 3100 includes an endeffector having a rotating interface 3112 which is freely rotatablerelative to the linkage arm 2108, a sagittal saw handpiece 3120, and ablade adapter 3130 coupling the sagittal saw handpiece 3120 to therotating interface 3112. The blade adapter 3130 may be configured tocouple any of the handpieces (e.g., surgical saw 1140 or 1240 orhandpiece 2112) described herein to any of the end effectors describedherein (e.g., end effector 1100, 1200, 1300, 1400, 1500, 1600, 1700,1800, or 1900). In order to achieve planar cuts, the rotating interface3112 may be guided to position a saw blade 3132 (e.g., saw blade 1242,2104, or 2204) in the plane in which it vibrates. The rotating interface3112 is configured to approach a target bone from a plurality of angles.In some examples, the rotating interface 3112 may be moved with threedegrees of freedom: translated in two directions on a plane and rotatedaround an axis normal to that plane.

As shown in FIGS. 34 and 35, the blade adapter 3130 has an end effectorinterface or first coupling mechanism 3140 at a first side (e.g., anupper side) of the blade adapter 3130 facing the rotating interface3112. The first coupling mechanism 3140 may include, for example, asidewall 3142 defining a cavity 3144 and one or more stages 3146projecting in a first direction (e.g., upward) within the cavity 3144.In some examples, the sidewall 3142 and stage 3146 may be concentric.The first coupling mechanism 3140 is sized, shaped, and/or configured toengage a mechanical interface 3148 (shown in FIG. 36) of the rotatinginterface 3112. For example, the mechanical interface 3148 may bepositioned within the cavity 3144 to facilitate coupling the rotatinginterface 3112 to the blade adapter 3130.

In some examples, the stage 3146 includes a base and one or moreprojections 3150 (shown in FIGS. 34 and 35) extending in the firstdirection (e.g., upward) from the base. The projections 3150 may bepositioned within one or more openings 3152 (shown in FIG. 36) definedin the mechanical interface 3148 for use in controlling a rotation ofthe blade adapter 3130 about a first axis 3154 (e.g., a vertical axis)(shown in FIG. 33). In this manner, the rotating interface 3112 may berotated about the first axis 3154 to rotate the blade adapter 3130, andthus also the saw blade 3132, about the first axis 3154.

A securing mechanism 3160 may be extended through the first couplingmechanism 3140 and/or mechanical interface 3148 to control a translationof the blade adapter 3130 along the first axis 3154 relative to therotating interface 3112. In this manner, the blade adapter 3130 may besecurely coupled to the rotating interface 3112. In some examples, thesecuring mechanism 3160 may include a captured screw that is preloadedby a spring located in the rotating interface 3112 (e.g., at themechanical interface 3148) to facilitate keeping the securing mechanism3160 from untightening (e.g., due to vibrations) during use of thesystem 3100.

In some examples, the saw blade 3132 may be quickly attached to anddetached from the blade adapter 3130 in the field. As shown in FIG. 35,the blade adapter 3130 may include, for example, a plate or lowerportion 3162 defining a channel 3164 (shown in FIG. 35) to prevent orrestrict movement of the saw blade 3132 relative to the blade adapter3130. In some examples, a first side (e.g., an upper side) of the lowerportion 3162 may be sized, shaped, and/or configured to receive the sawblade 3132 in the channel 3164 using a transition or interference fit.Additionally or alternatively, the blade adapter 3130 may include one ormore securing mechanisms 3166 extending through the lower portion 3162and/or saw blade 3132 to prevent or restrict movement of the saw blade3132 relative to the blade adapter 3130.

As shown in FIG. 36, the blade adapter 3130 may have a handpieceinterface or second coupling mechanism 3170 at a second side (e.g., alower side) of the blade adapter 3130 facing the handpiece 3120. Thesecond coupling mechanism 3170 may be sized, shaped, and/or configuredto engage a mechanical interface (a blade interface that attaches theblade 3132 to the handpiece) 3178 of the handpiece 3120 (shown in FIGS.34 and 35).

FIG. 38 is a flowchart of an example method 3200 for coupling an endeffector (e.g., rotating interface 3112) to a sagittal saw handpiece(e.g., handpiece 3120). The method 3200 includes providing a bladeadapter 3130 at operation 3210. The blade adapter 3130 may include afirst coupling mechanism 3140 at an upper side of the blade adapter 3130and a second coupling mechanism 3170 at a lower side of the bladeadapter 3130.

The first coupling mechanism 3140 is coupled to a mechanical interface3148 of the rotating interface 3112 at operation 3220. In some examples,the first coupling mechanism 3140 may include one or more projections3150. The projections 3150 may be inserted into one or more openings3152 defined in the mechanical interface 3148 to enable the rotatinginterface 3112 to rotate the blade adapter 3130 about a first axis 3154.In some examples, a securing mechanism 3160 is extended through thefirst coupling mechanism 3140 and/or mechanical interface 3148 to securethe blade adapter 3130 to the rotating interface 3112. The securingmechanism 3160 may include, for example, a captured screw or a pin thatextends through a clearance opening defined in the first couplingmechanism 3140 and is screwed into a threaded opening in the mechanicalinterface 3148 so that the blade adapter 3130 is clamped to the rotatinginterface 3112.

A saw blade 3132 may extend from the blade adapter 3130 in a directionperpendicular to the first axis 3154. In some examples, the bladeadapter 3130 includes one or more securing mechanisms 3166 that extendthrough clearance openings defined in a lower portion 3162 of the bladeadapter 3130 and in the saw blade 3132 and are screwed into threadedopenings in a body or upper portion of the blade adapter 3130 so that aproximate portion of the saw blade 3132 is clamped between the lowerportion 3162 and the upper portion of the blade adapter 3130. The secondcoupling mechanism 3170 is coupled to a mechanical interface 3178 of thehandpiece 3120 at operation 3230.

FIGS. 39-43 show another example system 3300 for coupling an endeffector 3312 to a sagittal saw handpiece 3120 (shown in FIGS. 33 and34). The system 3300 includes a blade adapter 3330 and a saw blade 3332coupled to the blade adapter 3330. As can be understood from acomparison of FIGS. 33-37 and FIGS. 39-43, the end effector 3312, bladeadapter 3330, and saw blade 3332 shown in FIGS. 39-43 are substantiallysimilar to the rotating interface 3112, blade adapter 3130, and sawblade 3132 shown in FIGS. 33-37, with some exceptions as shown in thedrawings and described herein.

As shown in FIGS. 40 and 41, the blade adapter 3330 has an end effectorinterface or first coupling mechanism 3340 at a first side (e.g., anupper side) thereof. The first coupling mechanism 3340 may include asidewall 3342 defining a cavity 3344 and one or more stages 3346projecting in a first direction (e.g., upward) within the cavity 3344.In some examples, the sidewall 3342 and stages 3346 may be concentric.The first coupling mechanism 3340 is sized, shaped, and/or configured toengage the mechanical interface 3348 (shown in FIG. 42) of the endeffector 3312. For example, the mechanical interface 3348 may bepositioned within the cavity 3344 to facilitate coupling the endeffector 3312 to the blade adapter 3330.

In some examples, the stages 3346 may have varying configurations. Forexample, a stage 3346 may include a base in which one or more openings3350 (shown in FIG. 40) are defined. The stage 3346 may be sized,shaped, and/or configured to receive one or more projections 3352 (shownin FIG. 42) of the mechanical interface 3348 extending in a seconddirection (e.g., downward). The projections 3352 may be positionedwithin the openings 3350 for use in controlling a rotation of the bladeadapter 3330 about a first axis 3354 (e.g., a vertical axis) (shown inFIG. 39). In some examples, the first coupling mechanism 3340 mayinclude one or more projections 3356 extending in the first direction(e.g., upward). The projections 3356 may be positioned within one ormore openings defined in the mechanical interface 3348 for use incentering the first coupling mechanism 3340 about the first axis 3354.

A securing mechanism 3360 may be extended through the first couplingmechanism 3340 and/or mechanical interface 3348 to control a translationof the blade adapter 3330 along the first axis 3354 relative to the endeffector 3312. In some examples, the securing mechanism 3360 includes acaptured screw or a headed pin that extends through a clearance openingdefined in the first coupling mechanism 3340 and is screwed into athreaded opening in the mechanical interface 3348 so that the bladeadapter 3330 is clamped to the end effector 3312.

The blade adapter 3330 may include, for example, an upper portion 3361and a lower portion 3362 configured to clamp the saw blade 3332therebetween. In some examples, the upper portion 3361 and lower portion3362 form a keyed joint to prevent or restrict relative movementtherebetween. The upper portion 3361 and/or lower portion 3362 maydefine a channel or recess 3364 in which the saw blade 3332 may bereceived to facilitate preventing or restricting movement of the sawblade 3332 relative to the blade adapter 3330. As shown in FIG. 41, aproximate portion of the saw blade 3332 may have an annular or ringconfiguration. Additionally or alternatively, the blade adapter 3330 mayinclude one or more securing mechanisms 3366 extending through the lowerportion 3362 and/or saw blade 3332 to prevent or restrict movement ofthe saw blade 3332 relative to the blade adapter 3330. In some examples,the securing mechanisms 3366 extend through clearance openings definedin the lower portion 3362 and saw blade 3332 and are screwed intothreaded openings in the upper portion 3361 so that the proximateportion of the saw blade 3332 is clamped between the upper portion 3361and lower portion 3362 of the blade adapter 3330.

As shown in FIGS. 41 and 42, the blade adapter 3330 may have a handpieceinterface or second coupling mechanism 3370 at a second side (e.g., alower side) of the blade adapter 3330. The second coupling mechanism3370 may be sized, shaped, and/or configured to engage a mechanicalinterface 3178 of the handpiece 3120 (shown in FIGS. 34 and 35). Forexample, the second coupling mechanism 3370 may define a radial slot3380 to an opening 3382 sized, shaped, and/or configured to receive aportion of the mechanical interface 3178. As shown in FIGS. 41 and 42,the opening 3382 may have a star-shaped configuration. In this manner,the handpiece 3120 may be securely coupled to the blade adapter 3330without being directly connected to the saw blade 3332.

FIGS. 44-48 show yet another example system 3400 for coupling an endeffector 3412 to a sagittal saw handpiece 3120 (shown in FIGS. 33 and34). The system 3400 includes a blade adapter 3430 and a saw blade 3432coupled to the blade adapter 3430. As can be understood from acomparison of FIGS. 33-37, FIGS. 39-43, and FIGS. 44-48, the endeffector 3412, blade adapter 3430, and saw blade 3432 shown in FIGS.44-48 are substantially similar to the rotating interface 3112, bladeadapter 3130, and saw blade 3132 shown in FIGS. 33-37 and/or the endeffector 3312, blade adapter 3330, and saw blade 3332 shown in FIGS.39-43, with some exceptions as shown in the drawings and describedherein.

As shown in FIGS. 45 and 46, the blade adapter 3430 has an end effectorinterface or first coupling mechanism 3440 at a first side (e.g., anupper side) thereof. The first coupling mechanism 3440 may include asidewall 3442, one or more stages 3446 projecting in a first direction(e.g., upward), and one or more flanges 3447 extending radially outwardfrom the sidewall 3442. In some examples, the sidewall 3442, stages3446, and flanges 3447 may be concentric. The first coupling mechanism3440 is sized, shaped, and/or configured to engage the mechanicalinterface 3448 of the end effector 3412 (shown in FIG. 47). For example,the mechanical interface 3448 may be positioned to circumscribe thestages 3446 and/or engage the flanges 3447 to facilitate coupling theend effector 3412 to the blade adapter 3430.

In some examples, the stage 3446 includes a base and one or moreprojections 3450 extending in the first direction (e.g., upward) fromthe base. The projections 3450 may be positioned within one or moreopenings 3452 (shown in FIG. 47) defined in the mechanical interface3448 for use in controlling a rotation of the blade adapter 3430 about afirst axis 3454 (e.g., a vertical axis) (shown in FIG. 44). In thismanner, the end effector 3412 may be rotated about the first axis 3454to rotate the blade adapter 3430, and thus also the saw blade 3432,about the first axis 3454. In some examples, the stage 3446 may defineone or more openings or gaps 3455 (shown in FIG. 45) sized, shaped,and/or configured to receive one or more projections 3458 (shown in FIG.47) of the mechanical interface 3448. The projections 3458 may bepositioned within the gaps 3455 for use in orienting or aligning thefirst coupling mechanism 3440 about the first axis 3454.

A securing mechanism 3460 may be extended through the first couplingmechanism 3440 and/or mechanical interface 3448 to control a translationof the blade adapter 3430 along the first axis 3454 relative to the endeffector 3412. In some examples, the securing mechanism 3460 includes acaptured screw that extends through a clearance opening defined in thefirst coupling mechanism 3440 and is screwed into a threaded opening inthe mechanical interface 3448 so that the blade adapter 3430 is clampedto the end effector 3412.

As shown in FIG. 47, the blade adapter 3430 may have a handpieceinterface or second coupling mechanism 3470 at a second side (e.g., alower side) of the blade adapter 3430. The second coupling mechanism3470 may be sized, shaped, and/or configured to engage a mechanicalinterface 3178 of the handpiece 3120 (shown in FIGS. 34 and 35). Forexample, the second coupling mechanism 3470 may define a radial slot3480, a contoured edge 3481, and one or more openings opening 3482configured to receive a portion of the mechanical interface 3178. Inthis manner, the handpiece 3120 may be securely coupled to the bladeadapter 3430 without being directly connected to the saw blade 3432.

FIGS. 49A, 49B and 50 show one aspect of the present invention. FIG. 49Ashows a standard blade interface 3178 in which a blade lock has beenremoved. The blade interface 3178 is typically removably attached to themain drill 3120. Instead, the headed pin 3160 is inserted through wherethe blade lock had been located. The headed pin 3160 has an externalthreading that is threaded into an internal threading of the rotatinginterface 3112. When inserted through the blade interface 3178, thenthrough blade adapter 3130 and then through rotating interface 3112, andthreaded into the rotating interface, the headed pin 3160 locks theblade interface 3178, blade adapter 3130 and the rotating interface 3112of the end effector 3100 together so that they can rotate or articulatetogether. As seen in FIG. 50, at least a part of the pin 3160 (e.g., apart of the head of pin head) is captured/positioned inside the bladeinterface 3178 as well as in the blade adapter 3130 and the rotatinginterface 3112 to provide the rigidity between the handpiece 3120 andthe blade 3132 such that any downward or upward motion of the handpiecedoes not cause the blade to bend at the interface around the headed pin3160. In the embodiment shown in FIGS. 49-50, it is also important tonote that the blade 3132, the blade interface 3178, blade adapter 3130and the rotating interface 3112, all rotate or oscillate around the samevertical axis 3154 (see FIG. 33), which is co-linear with handpieceinterface oscillation axis. If the standard blade interface 3178 doesnot allow for the insertion of the headed pin 3160, a slightmodification of the blade interface may be necessary. The concept of thepin 3160 being positioned inside the blade interface 3178, blade adapter3130 and the rotating interface 3112 for stabilizing the blade can beimplemented through all of the embodiments as shown in FIGS. 33-48.

Further Definitions and Embodiments

Example systems and methods for coupling an end effector to a sagittalsaw handpiece are described herein and illustrated in the accompanyingdrawings. This written description uses examples to disclose aspects ofthe disclosure and also to enable a person skilled in the art topractice the aspects, including making or using the above-describedsystems and executing or performing the above-described methods.Examples described herein allow a sagittal saw handpiece to be rigidlycoupled to an end effector arm of a robot to actuate a saw blade, whichimproves the feeling from a user's perspective. Moreover, because thehandpiece is not directly connected to the saw blade, the blade guidanceand actuation axes alignment is controlled and ensured, the risk of thesaw blade breaking at the interface due to misalignment of the bladeguidance and/or actuation axes is mitigated, and the risk of aself-detaching handpiece is also mitigated. Furthermore, the interfaceis agnostic from the handpiece system. This provides flexibility interms of integration with off-the-shelf handpieces. That is,modification to off-the-shelf handpieces are reduced and there is noneed to “rework” the handpiece body.

The foregoing description is merely illustrative in nature and is in noway intended to limit the disclosure, its application, or uses. Unlessdefined otherwise, all technical and scientific terms used herein havethe same meaning as commonly understood by one of ordinary skill in theart to which the disclosure belongs. It will be further understood thatterms, such as those defined in commonly used dictionaries, should beinterpreted as having a meaning that is consistent with their meaning inthe context of this specification and the relevant art and will not beinterpreted in an idealized or overly formal sense expressly so definedherein. The broad teachings of the disclosure can be implemented in avariety of forms. Therefore, while this disclosure includes particularexamples, the true scope of the disclosure should not be so limitedsince other modifications will become apparent upon a study of thedrawings, the specification, and the following claims. It should beunderstood that one or more steps within a method may be executed indifferent order (or concurrently) without altering the principles of thepresent disclosure. Further, although each of the embodiments isdescribed above as having certain features, any one or more of thosefeatures described with respect to any embodiment of the disclosure canbe implemented in and/or combined with features of any of the otherembodiments, even if that combination is not explicitly described. Inother words, the described embodiments are not mutually exclusive, andpermutations of one or more embodiments with one another remain withinthe scope of this disclosure.

Spatial and functional relationships between elements (for example,between modules) are described using various terms, including“connected,” “engaged,” “interfaced,” and “coupled.” Unless explicitlydescribed as being “direct,” when a relationship between first andsecond elements is described in the above disclosure, that relationshipencompasses a direct relationship where no other intervening elementsare present between the first and second elements, and also an indirectrelationship where one or more intervening elements are present (eitherspatially or functionally) between the first and second elements. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. The term “and/or” includes any and all combinations of one ormore of the associated listed items. As used herein, the phrase at leastone of A, B, and C should be construed to mean a logical (A OR B OR C),using a non-exclusive logical OR, and should not be construed to mean“at least one of A, at least one of B, and at least one of C.”

It will be understood that although the terms first, second, third, etc.may be used herein to describe various elements/operations, theseelements/operations should not be limited by these terms. These termsare only used to distinguish one element/operation from anotherelement/operation. Thus, a first element/operation in some embodimentscould be termed a second element/operation in other embodiments withoutdeparting from the teachings of present inventive concepts.

As used herein, the terms “comprise”, “comprising”, “comprises”,“include”, “including”, “includes”, “have”, “has”, “having”, or variantsthereof are open-ended, and include one or more stated features,integers, elements, steps, components or functions but does not precludethe presence or addition of one or more other features, integers,elements, steps, components, functions or groups thereof. Furthermore,as used herein, the common abbreviation “e.g.”, which derives from theLatin phrase “exempli gratia,” may be used to introduce or specify ageneral example or examples of a previously mentioned item, and is notintended to be limiting of such item. The common abbreviation “i.e.”,which derives from the Latin phrase “id est,” may be used to specify aparticular item from a more general recitation.

In the figures, the direction of an arrow, as indicated by thearrowhead, generally demonstrates the flow of information (such as dataor instructions) that is of interest to the illustration. For example,when element A and element B exchange a variety of information butinformation transmitted from element A to element B is relevant to theillustration, the arrow may point from element A to element B. Thisunidirectional arrow does not imply that no other information istransmitted from element B to element A. Further, for information sentfrom element A to element B, element B may send requests for, or receiptacknowledgements of, the information to element A. The term subset doesnot necessarily require a proper subset. In other words, a first subsetof a first set may be coextensive with (equal to) the first set.

Example embodiments are described herein with reference to blockdiagrams and/or flowchart illustrations of computer-implemented methods,apparatus (systems and/or devices) and/or computer program products. Itis understood that a block of the block diagrams and/or flowchartillustrations, and combinations of blocks in the block diagrams and/orflowchart illustrations, can be implemented by computer programinstructions that are performed by one or more computer circuits. Thesecomputer program instructions may be provided to a processor circuit ofa general purpose computer circuit, special purpose computer circuit,and/or other programmable data processing circuit to produce a machine,such that the instructions, which execute via the processor of thecomputer and/or other programmable data processing apparatus, transformand control transistors, values stored in memory locations, and otherhardware components within such circuitry to implement thefunctions/acts specified in the block diagrams and/or flowchart block orblocks, and thereby create means (functionality) and/or structure forimplementing the functions/acts specified in the block diagrams and/orflowchart block(s).

These computer program instructions may also be stored in a tangiblecomputer-readable medium that can direct a computer or otherprogrammable data processing apparatus to function in a particularmanner, such that the instructions stored in the computer-readablemedium produce an article of manufacture including instructions whichimplement the functions/acts specified in the block diagrams and/orflowchart block or blocks. Accordingly, embodiments of present inventiveconcepts may be embodied in hardware and/or in software (includingfirmware, resident software, micro-code, etc.) that runs on a processorsuch as a digital signal processor, which may collectively be referredto as “circuitry,” “a module” or variants thereof.

It should also be noted that in some alternate implementations, thefunctions/acts noted in the blocks may occur out of the order noted inthe flowcharts. For example, two blocks shown in succession may in factbe executed substantially concurrently or the blocks may sometimes beexecuted in the reverse order, depending upon the functionality/actsinvolved. Moreover, the functionality of a given block of the flowchartsand/or block diagrams may be separated into multiple blocks and/or thefunctionality of two or more blocks of the flowcharts and/or blockdiagrams may be at least partially integrated. Finally, other blocks maybe added/inserted between the blocks that are illustrated, and/orblocks/operations may be omitted without departing from the scope ofinventive concepts. Moreover, although some of the diagrams includearrows on communication paths to show a primary direction ofcommunication, it is to be understood that communication may occur inthe opposite direction to the depicted arrows. Many variations andmodifications can be made to the embodiments without substantiallydeparting from the principles of the present inventive concepts. Allsuch variations and modifications are intended to be included hereinwithin the scope of present inventive concepts. Accordingly, the abovedisclosed subject matter is to be considered illustrative, and notrestrictive, and the appended examples of embodiments are intended tocover all such modifications, enhancements, and other embodiments, whichfall within the spirit and scope of present inventive concepts. Thus, tothe maximum extent allowed by law, the scope of present inventiveconcepts are to be determined by the broadest permissible interpretationof the present disclosure including the following examples ofembodiments and their equivalents, and shall not be restricted orlimited by the foregoing detailed description.

What is claimed is:
 1. A system for robot-assisted knee arthroplastysurgery, comprising: an end effector having a first mechanicalinterface; a sagittal saw handpiece having a second mechanicalinterface; and a blade adapter configured to couple the end effector tothe sagittal saw handpiece, the blade adapter comprising a firstcoupling mechanism at a first side of the blade adapter and a secondcoupling mechanism at a second side of the blade adapter, the firstcoupling mechanism coupleable to the first mechanical interface, thesecond coupling mechanism coupleable to the second mechanical interface.2. The system of claim 1, wherein the first coupling mechanism defines acavity for receiving the first mechanical interface therein.
 3. Thesystem of claim 1, wherein the first coupling mechanism includes asidewall defining a cavity and one or more stages within the cavity. 4.The system of claim 3, wherein the first mechanical interface definesone or more openings for receiving the one or more stages therein. 5.The system of claim 3, wherein the one or more stages include a base andone or more projections extending from the base.
 6. The system of claim3, wherein the first mechanical interface includes one or moreprojections, and the one or more stages define one or more openings forreceiving the one or more projections therein.
 7. The system of claim 1,wherein the first coupling mechanism includes one or more projections,and the first mechanical interface defines one or more openings forreceiving the one or more projections therein.
 8. The system of claim 1,further comprising a securing pin extendable through the firstmechanical interface, the blade adapter and the second mechanicalinterface along a common axis of rotation or oscillation.
 9. The systemof claim 1, wherein the blade adapter comprises an upper portion and alower portion configured to receive a saw blade therebetween.
 10. Thesystem of claim 9, wherein the lower portion defines a channel forreceiving the saw blade therein.
 11. The system of claim 9, furthercomprising a securing mechanism extendable through the lower portion toclamp the saw blade between the lower portion of the blade adapter andthe upper portion of the blade adapter.
 12. The system of claim 1,wherein the second coupling mechanism defines a radial slot and one ormore openings for receiving one or more portions of the secondmechanical interface.
 13. A blade adapter for coupling an end effectorhaving a first mechanical interface to a sagittal saw handpiece having asecond mechanical interface, the blade adapter comprising: a firstcoupling mechanism at a first side of the blade adapter, the firstcoupling mechanism coupleable to the first mechanical interface; and asecond coupling mechanism at a second side of the blade adapter, thesecond coupling mechanism coupleable to the second mechanical interface.14. The blade adapter of claim 13, wherein the first coupling mechanismincludes a sidewall defining a cavity and one or more stages within thecavity.
 15. The blade adapter of claim 14, wherein the one or morestages include a base and one or more projections extending from thebase.
 16. The blade adapter of claim 13, further comprising a securingmechanism extendable through the first coupling mechanism to clamp thefirst coupling mechanism to the end effector.
 17. The blade adapter ofclaim 13, further comprising an upper portion and a lower portionconfigured to receive a saw blade therebetween.
 18. The blade adapter ofclaim 17, further comprising a securing mechanism extendable through thelower portion to clamp the saw blade between the lower portion of theblade adapter and the upper portion of the blade adapter.
 19. The bladeadapter of claim 13, wherein the second coupling mechanism defines aradial slot and one or more openings for receiving one or more portionsof the second mechanical interface.
 20. A method of coupling an endeffector having a first mechanical interface to a sagittal saw handpiecehaving a second mechanical interface, the method comprising: providing ablade adapter comprising a first coupling mechanism at a first side anda second coupling mechanism at a second side; coupling the firstcoupling mechanism to the first mechanical interface; and coupling thesecond coupling mechanism to the second mechanical interface.